As the title says I'm looking for two things. Better body and head replacers, and immersive food and sleep mods.
I've already seen Real Hunger but I was dubious, as it seems to add bunches of unnecessary things, and since I'm running many item mods I wonder if the scripted nourishment would work with some OOO added foods.

Just putting it out there, does anyone have any recommendations for these?

Roberts is the most popular male body replacer, I would say HGEC is the most popular female body replacer, followed by Roberts female judging by posted Load Orders in Forums. For the heads question, I am assuming you are talking about a Cosmetic Compilation, like Beautiful People,COBL races, or Race Balancing Project (RBP).I do not use hunger/exhaustion/sleep mods, but if it has been designed to work with COBL, it will work with OOO provided you install the proper esp's for COBL and OOO to work together.EDIT I use a high resolution texture replacer for female bodies, and I use a texture replacer for "Female" heads that matches the female body textures. The problem is that Male bodies have a different texture than female bodies, but they share the same Head textures. I can live with this on my game, but it can be extremely obvious on certain races.

For Hunger/Sleep mods, you may take a look at http://www.gamesas.com/index.php?/topic/1097149-hunger-thirst-and-sleep-oh-my/. I of course recommend my own http://www.gamesas.com/bgsforums/index.php?showtopic=881496, but also note that tejon's http://www.gamesas.com/index.php?/topic/1162461-relz-bare-necessities/ has been updated since that thread. A bit on the side, but I also recommend my http://www.gamesas.com/index.php?/topic/1141697-relz-map-marker-overhaul/, which actually makes it possible/likely to get lost, thereby making the hunger/sleep mods much more interesting and useful.