Almost every other DLC for any type of game like this works together. Look at ELITE DANGEROUS as an example. They have the Planetary Landing Version/DLC if you will and the reg. You and I can play together, and if you have the 'Reg-Space Only version' then you just don't get the options to buy the Landing Stuff, get offered missions to Land, and obviously, cannot land on a Planet.
The only times I see DLC not affecting each other is where the DLC is (in essence) a completely seperate game, and in this case it is not, it is an AddOn, so if your game does not have the Urban Mission, then you likely will not get missions in Urban Areas (nor have access to the new mechs).
Again, I don;t know, just how I've seen things like this work in the past.
I play ED but its singular DLC doesn't do this really, you either have access to DLC features or don't. Otherwise everyone comes in patches, and everyone has all content whether or not they access it, it is like MMO in this sense.
A good example of DLC not talking together would be the Elder Scrolls and Fallout series (under Betheda), where DLCs features don't interact unless scripted to do so, something Bethesda never did, leading to things like perks no affecting DLC weapons or spells (or not doing that properly). This isn't exactly noticeable at a glance, especially since none of those DLCs add new features really, but the issue is there.
BattleTech's DLC are seemingly going to be addons in similar manner as TES/FO DLC, so features working together is a question. So, when Urban Warfare comes out, will urban terrain be an option in flashpoints, or will jungle biome work with whatever new thing UW will come with? Or will the new mission type work with all future biomes? If it comes with infantry (just random example of what could be) or other new features, would that be incorporated into flashpoints?
This is a thing i'm concerned about. DLC gameplay features existing as islands in certain games is very, very disappointing.