... seriously did you actually play the game in vanilla before leaping into FWE + MMM? Mods designed to make the game more challenging (no not impossible).
Fawkes can't be hired until waaaaay through the main quest line (and your max companions depends on the setting anyway).
Companions do restore health after fights but it doesn't happen instantly... but then thats vanilla not modded.
Ammo weight was added as part of FWE to stop you carrying round 20000 rounds of ammunition, 50 missiles and 20 mini nukes wherever you went.
https://sites.google.com/site/fo3wanderersedition/detailed-changes/05actors#TOC-Followers-Enhanced-FWE-Optional-Mod Says it all. Seriously... try reading what the mods actually change.