Just some advice from my experience of being a tester and hearing mappers talk about the problems they've faced.
I plan on having 2 different Panther textures, one of them being new (if I have enough time to make it). Same goes for other vehicles.
I would just keep it to one for now. You can use a placeholder (like the Normandy one or w/e) and reskin that one with the new texture after the map is complete. IF you have the space after the map is finished you can add a 2nd panther texture. Changing the types of vehicles is always relatively easy to do even after the map is complete.
It's really cool for tanks to have slightly different camos and vehicle numbers like irl. But tbh, people don't really notice that stuff in the heat of battle. Overall the memory that is saves is more beneficial than the 'aesthetic' factor.
I also want to clone some buildings to have 2 different textures for the same building on the same map. Keep in mind this map is (I think) the biggest city map made for FH2 and it´s hard to make sectors look different since there is a limited number of buildings to choose from.
Same advice as above. It's best right now to keep the building's textures the same so you don't load too many at once. IF you have memory left over after the map is finished and the areas still look too repetitive, then I'd look into re-skinning it.
Lots of games re-use assets throughout a map to save memory. The trick is spreading out the similar buildings so the player doesn't encounter them in the same view. The important places are flag areas where players will generally spend most of their time. That's where you can utilize the unique statics so no two flag zones look the same.
If you have two areas with the same set of buildings in them. I would try a different approach of making the details different first; i.e. re-ordering the buildings so they're not in the same order. Making the street scene different (different debris in the road, lay out the cover differently etc...) so the player can't automatically tell that the same buildings are used.
It's definitely one of the tougher parts of urban mapping, but if you show some problem areas. We could certainly take a look and make some suggestions.
Same goes for open buildings. Some times I did not intend to place open buildings but some are unique (they don´t come in closed version) so that forces me to close them with wood planks and stuff like that.
Like Slayer said, I would look for other statics to fill that area. If you simply close off an open building, the textures inside that building will still be loaded and the lightmaps will still be generated for an area that a player can't access. If you want to go
really hardcore, you could make a closed version of that static after the map is done. But that seems unnecessary, since most times you can just find other statics to take it's place.
Panther texture is nice.
In my experience I would just worry about vehicle textures last. If the map is well optimized and has good gameplay, someone maybe able to save you the trouble of re-skinning a tank from scratch. Overall, you want to have a strong map that plays well and runs well on everyone's computer so it can be played for many years to come.
EDIT:
Also, pretty sure Toddel made the Panther texture in a clever way so that it can have two different sets of turret numbers on the same map. Best to save that till the end.