1. Ah, OK, I understand. Just saying that you could also issue some production orders. Maybe make some prototypes of your robots built. It's not like they'd cost you anything.
2. Yeah, what I was describing was less of a frontline unit and more of a support unit, a mobile hospital/repair pit if you will, something you could use to repair battlesuits and much larger vehicles while the repair bots skitter around and bring in wounded from the frontlines or make simple field repairs or bring in raw materials they scavenge. It could even act as a mobile war factory if it's advanced enough. Not the same production capabilities as Hephaestus of course, but it could have the repair bots assemble simple stuff, provided it has the raw materials. But anyway, if our stuff is cheap enoug and mass produced enough, that thing would probably be useless, since sods or your repair robots could do the same job.
3a. From when I was keeping track of the stockpiles on Canary Base, I remember that active robots need about a nutrient pack a month. Hibernated robots could probably last even longer. So having the sods activate once every 6 months, go to a stockpile to "eat" and then go back to storage (maybe even help some of their comrades that have been damaged by wear and tear) shouldn't be very expensive. And I don't think sod brains will go "stale", although you should probably check that to make sure.
Hmm... There's another problem with robosods: They can't eat and you can't eat them. Except for their brains, I suppose. But you'll have to crack their braincase open. Like nuts. Joking aside, a mobile nutrient pack recycling unit (put in spent nutrient packs and food, gain full nutrient packs) would be a good idea.
3b. Even if they cost more or if you lack the facilities to gain enough biomass to make enough nutrient packs, it's not like building extra facilities would be a problem. Extra fleshpits would take time to build and you shouldn't dedicate all your production on that. In the meantime, you could do anything. Research better farms. Tow some asteroids in an orbit near Hephaestus and turn them into farms that take raw materials from one of the other planets in the solar system, use some ultra-efficient genemodded bacteria to convert them into suitable form and send them to hephaestus to be made into nutrient packs. Build space elevators that double as shipyards to move resources around. Or mass drivers. Make a contract with whatever company prevailed in the food chain wars to provide you with unlimited pizza (Demolition Man says Pizza Hut). Anything you want, you can do. The world is your oyster.