Here's why its a bad idea then
1. Giving suppresion to infantry is a bad idea, something we have learned long ago, there's a reason we only get it via ability (Rear Echelons) that has been nerfed into near-uselessness or Vet 5 Obersoldaten(Or has it been removed already? i don't remember)
2. The amount of suppresion given would either be so low you would need to mass Conscripts to see any effect (pro tip: we don't want that) or it would be so powerful it could be classified as "cancer incarnate" (we don't want that either)
3. Limiting suppression to green cover only doesn't really work on infanrty that can build its own green cover
4. Seriously, we don't want suppression on infantry, really.
5. Outisde of suppresion, even if it is technically possible to have Maxims be part of a regular inf squad, and even if it is possible le to make it work without being clunky, buggy and with broken animations, no one will actually go through with the effort to get the same result as simply giving them literally any other LMG we already have in the game, and having it behave the way you suggested (limited movement speed, long setup time). Its a cool looking gimmick at best.
1. I don't recall mass RE's or even the Para's with LMGs being particularly cancerous.
2-4. So basically a conscript blob is going to march right up to your infantry, build a piece of cover for all of them mid combat? Even if this does happen guess what. You can walk away.
5. All the animations are already there. On top of being a cool gimmick it should also cut all the conscript and maxim whining in half.