This smaller mutant sounds like the Troglodytes encountered in The Pitt (DLC for FO3), or, it could be Centaurs which have been in all the games from Fallout to FONV
Neither of them use weapons though.
There is the option to have lower level mobs be like Radscorpions (Have appeared in all games), mutant ants, etc.
Plenty of weak mobs that can be used starting out.
Also, are you exclusively sticking to the original 3 Fallout for weapons, art, etc? I feel some of the changes made in FO3 and NV have been improvements, particularly with the laser rifle.
It may also be a good idea to include a random setting from a list of possible ones for the vault, related to the typical social experiments that were run in the vaults. This could change the starting resources, starting level of some survivalists, starting classes available to the player, etc.
How bout different super mutant variants? We already know super mutants continue to grow and sometimes reach tremendous size and power (Super Mutant Behemoth) and they have began evolving in New Vegas.
Thereās a Roman civ mod being worked on already by @Moe2212. If he agrees you could likely borrow many of his assets and redecorate them to include Caesarās Legion in the mod.
Glad to see new interested people I had planned to work on this more when the first few builds come out. Mainly so I can see how the code worked and how the idea could fit into it, but also to see what assets they can make and that I can use / change. No point in me reinventing the wheel if I can do other things
True, I also think this would make a fun set of modules for the player to discover. Iād personally like to start out with a generic vault, then let the expeditions go out and discover all those wacky vaults plus all the ones we can dream up. But it can go either way once the mod ball gets rolling.
I tend to start with the classic 1 & 2, then use the new 1st person fallouts when necessary. But Iām cool with whatever looks good.
Oh manā¦ This popped into my head the other day, didnāt know it had already been thought up. Iād love to see a vault-building (expanding?) fallout mod in action!
Some ideas if this ever kicks off - gunsmith class that can build progressively more kick-ass guns as he levels, another class that can salvage busted power armor and refurbish it, scavenger class that scouts out ruins for food/ammunition/supplies, raiders driving in Mad Max style and looting your stuffā¦ fat man craters!! (cāmon, you know you wanna see it!)
Wow Iāve never gotten to play any of the fallout games! But your mod might get me very intrested! Hope progress is steady! Canāt wait to try it out!
Iām probably going to create a vault of my own to give you a few ideas on other ways the vaults are created. By the way i love the idea for this mod and the progress so far is amazing cant wait to see more.
Itās not really a finished thing, I literally downloaded Qubi 2 hours ago and fiddled with it. More of a āthis is what I can doā than a"this is all Iām doing" thing.
Pointing out that i do NOT actually have this game (waiting for steam edition, i see it come out, im jumping on that), but being a sandbox fanatic, i saw this game and watch a few videos, instantly hooked, now i see something like this, my jaw dropped faster than the bombs fell. if itās not already obvious, iām a huge fan of the fallout series, i would love to see something like this come to be, as iām sure any other fallout fans would (the following above), and i would love to helpā¦ only issue is most i could give is modeling (when i have the program) and help on concept (which we have here already due to the support of the other 98 comments here), but overall, if this is still being done, i have to say, Do, Not, Stop.
I had planned to work on this more when the first few builds come out. Mainly so I can see how the code worked and how the idea could fit into it, but also to see what assets they can make and that I can use / change. No point in me reinventing the wheel if I can do other things 
sorry. Too busy elsewhere, plus its so far away from the game release its hard to be go go go on it. Still here thou!
