So I've read side missions are only available for so long, but is there any warning which ones you'll miss if you continue on, or can you at least revert to a save to do them if you missed any? I think I also read your allies can get killed or leave you for various reasons if you don't keep them happy. Have you had that happen, or is it pretty easy to keep them? This is one of my main concerns, and why I said earlier I was hoping there isn't a lot of micromanaging. It's because I plan to progress to harder difficulty modes.
You can revert to previous saves anytime yes, but it's kind of pointless to do so if a particular mission expires, as every mission you assign to teammates is pretty standard; find food rations, ammo, or medical supplies. Even if you miss one another similar one will pop up, it's pretty basic and I usually just have my team find food rations and medical supplies (I can craft shotshells myself) because I know not to take stuff like that for granted in a survival game. You simply have to have some logistical common sense to survive in most SURVIVAL games. Yes, allies can die in a mission but I only assign my team missions if they have a 80%+ chance of success so I never send them on real dangerous missions which net rewards I can most certainly find myself when I myself go on a mission, as I stated, I already managed to build everything in my base so it's not like I need to risk teammates death for pointless net gain.
And yes, you gotta keep your team happy but that isn't too hard, just build stuff that provides comfort for them in base and give them double rations after they successfully complete a mission and occasionally do something in a dialogue option that makes them happy and they shouldn't rebel, but of course only recruiting people you like helps big there.
Common sense really, but you probably do need basic managerial skills in resource allocation and scrounging (your PDA device picks up resources in zones, which I usually comb thoroughly and acquire before I exit the mission) to get through smoothly but I've learned that many players don't have that and just want to play like GTA or Doom or something.