However, your strategy won't work, for a variety of reasons.
Alright, so my strategy was truncated for the sake of convenience. I'll replay the mission so I can go step-by-step.
Start by deploying a tough shocktrooper in the upper right corner of your little square (who should be able to survive any interception fire, as they spawn directly in cover, otherwise, spawn two shocktroopers or whatever you want in the top, middle two areas to protect the base and protected from fire on all sides, obviously make sure Rosie is deployed for extra CP). Deploy Alicia and Largo inside the base as far to the right as you can.
Immediately begin by running Largo to the right, DIRECTLY BEHIND a tank and then blowing it up. Tank gone.
Strategy. Largo will be ignored for the rest of the game both by you and enemy units provided you leave him behind the building.
Order "Caution" onto Alicia and run her up the right side, killing the shocktrooper, then end her turn being able to see both the gatling turret and sniper elite and gatling turret. Alternately, run a shocktrooper up to kill the other shocktrooper, and have Alicia kill the sniper elite - this will better protect your shocktrooper in the corner at the beginning and make the enemy lose a (useless) CP. Immediately after that, order another turn, and have Alicia run down the stairs in front of the gatling turret to capture a base and move on, using ragnaid if necessary. Move Alicia a final time, having her kill a Sniper Elite as she runs to get near the gatling turret on the far right of the map.
Summon a lancer from the recently captured base. End your turn.
Have the Lancer move twice, on the second turn killing the gatling on the far right of the map.
Move Alicia up the right side of the map, capturing the base in the top-right corner. Position her behind a sandbag, or have her take another turn and kill the sniper who should be near that base. It doesn't really matter.
Summon a Lancer from the new base (or two). Summon two shocktroopers from the new base. End your turn. I guess you would use demolition boost on Alicia and blow up the tank, you have more than enough CP.
Have the Lancer you summoned blow up the tank by
walking behind it. Have the other Lancer, if you summoned one and really want to do this, waltz up the top center and clear the Tank Destroyer at the top (you can get behind it well enough to kill it in one hit) and maybe try to kill the completely useless Heavy Tank that does nothing the entire game in the center of the map with the same Lancer.
Have the two shocktroopers run up and take the base in the top middle, killing the sniper elites on the way.
Have Alicia run over to the right side and find out where Selvaria is. It doesn't matter if she dies at this point. If Selvaria close enough, have the two shocktroopers kill her. If not, don't. I'm sure by now, you know how to use a decoy to turn her around and another soldier to blast her in the head and kill her quickly (if you didn't get Alicia killed, you only need one of the previous shocktroopers and can use her as a decoy). If you really need to, you can use caution and/or attack and defense boost... You have enough CP to do whatever you want.
There. You just
really easily beat Ghirlandaio in three or four turns (highest rank possible) with hilariously excess CP by having a scout zip straight to the important places and having lancers walk behind tanks.
Yes, this requires knowledge of how the level works in advance, but only a bit. The level is incredibly punishing the first time around because you have no idea where anything is or how to kill Selvaria, but there are many VC2 levels that are equally ridiculous the first time. These same tactics used to dominate this mission dominate almost every mission in the game and make them require only basic strategy. Caution is really the only command I ever need to use to completely break an entire level, and I generally only have to use it once - just like in this level! Even without using it, the strategies rarely become more complex. Heck, if I had been patient, or used demolition boost and just had Alicia kill the gatling turrets, I could have finished the level without using caution or any commands at all.
Most difficult VC2 missions require considerably more strategy than this (although the difficult ones are often spread out by filler missions or unlocked post-game), and many of the easier missions that are useful to replay for parts/exp have enemy placement/boxes you need to retrieve move around. This makes it fun (for me, anyway) and challenging to be able to finish these missions as quickly as possible.
VC1 suffered heavily because of reinforcements not coming in on the same turn they were summoned (which made it stupidly easy to steamroll the opponent) and having the objective generally just be "get here" or "kill that." VC2 is much more complex in that you have to defend multiple positions, and enemies can unexpectedly call in tons of reinforcements if you don't manage to secure your perimeters.
Tanks can't capture bases!? Are you serious!? Gee, it couldn't have possibly been implied that I meant you clear the base with the Edelweiss and take it with someone else.
Come on, dude, like I would argue something that ridiculous. I did get my strategy a little mixed, though, so I'll type it out.
Move the Edelweiss to the first boss, launch a mortar and kill the shocktrooper in the back. Move the Edelweiss again, this time shooting the tank in the back (with the amazing strategy of just getting behind it) and killing it in one hit, turn the Edelweiss around so that it is looking at the street, but not in site of the Lupus, and knock the shocktrooper so that he's facing the Edelweiss.
Run an engineer (preferably Dallas, cause I love her so much) up to the base and kill the shocktrooper, then capture the base. End your turn.
The enemy's turn will likely do nothing that really hinders you, except possibly hurt a Lancer you positioned in your central base.
Spend a bunch of CP having your Lancers NUKE THE HELL out of the Lupus, use the Engineer (if necessary) to refill ammo. Lancers should have their unlocked potentials by this point, so use the ones with Ultimate Anti-Armor and hope it activates. Provided you had enough Ultimate Anti-Armors activate, you can nuke the shell of the Lupus incredibly quickly, if not, you should still be able to take care of it.
Move the Edelweiss up to the lupus, shoot it. Move it behind it on a second movement and kill it. Level over.
See my strategy that still ends the mission incredibly quickly
I devised both of these strategies by myself, and rather quickly for the one in Ghirlandaio (it wasn't until I was on my second run through the game that I found how easily the battle against Jaeger was broken, it had initially given me more trouble than any other mission in the game).
Most of my challenges the first time through VC were from learning exactly how the mechanics of the game operate. Using that knowledge playing VC2, I definitely had an easier time going through the story, but still felt that many points in it required more thinking than VC1's story's most difficult parts.
What I liked about the defensive missions was that, alternatively, to get an A-Rank, they were seek-and-destroy missions where you couldn't leave a single unit alive (which is the only thing I would do). It added variety to the game and additional challenge.
Like I've said repeatedly, you can play VC2 from the beginning of the story to the end of the story without caring about rank and with only a few challenging missions. My first time through every single story mission that I finished (I would sometimes fail a couple times on some of the more challenging levels before I understood exactly what to do - I found it very confusing how to kill Dirk, at first, for example) aside from one single tutorial level netted me an A-Rank (although I still found it difficult to get several, more difficult than most VC1 missions). Going through the optional content and making sure I had full A's was much more challenging than anything in VC1, however.
Come on, dude, like I would argue something that ridiculous. I did get my strategy a little mixed, though, so I'll type it out. 