For the most part, these are all things I cannot specifically give answer to;
- the pads all depend on how many total jack points you have, the loading to each, how each is to be based and what type of jack is used.
-how any drain tile is handled will depend on what overall method is used.
-rebar placement will need to be much more regular when using "placed" concrete (your old boss was being correct in his proper terminology); exact placement & spacing will be based on what your local code requires, likely to be more near 16" centers, vertically & horizontally. When it comes to doing your new walls in block, I'm not going to be of much help; I don't do much at all in below-grade structural block work. This again, will go back to your local codes.
-assembling new walls from precast sections could be done, but you do run into concerns of needing several spaces large enough to cast sections, strategically placed around the basement to be near the installation points, and the logistics of safely handling & maneuvering them. Ideally if you were to use precasts, they would be laid around the perimeter, outside, and lowered into place with heavy equipment.
Meanwhile, I'll be thinking on this further, and post any added thoughts as they come along. Did I read correctly that the footprint dimensions on the home are 20' X 28', and that moving the home completely off the foundation, in any direction, is not a possibility?