Welcome Rhino! I'm building a pond in Spingfield, NE so not far from you. Sounds like you have done your research and are certainly headed in the right direction. You've definitely found the right place to help finish the job.
1. With largemouth bass, it is certainly safe to add golden shiners. Will only help that forage base for those bass, especially early on. The bass will clean them up, much like the fatheads, but they should last a little longer for you.
2. You don't want your bluegill to get too much of a head start, but you do want to make sure their population is established prior to introducing your largemouth. I honestly wouldn't put too much time in between stocking your bluegill and your bass. Possibly just a single spring. Wait as long as you like to let the fatheads and shiners do their thing.
3. Let a largemouth bass expert answer this one, but for our region, I'd refer to my suggestion above. Don't stock them too long after your bluegill. I suppose if large bass is your primary goal, that time frame between stocking bluegill and bass could be expanded.
4. If you were going to add yellow perch, you'll need plenty of vegetative cover for them to evade largemouth bass predation. Without, the bass will clean them up and probably pretty quickly. No harm can be done by adding walleye however, a mistake often made is adding walleye that are bite size for bass. Either add advanced sizes so they are not expensive food for your bass or grow them out in cages. Downside to growing them out in cages is they do tend to be slow growers and obviously thrive more in open water.
5. I'd wait on grass carp and see how your vegetation sets up for you. No need to rush something not needed at the moment. If something becomes a problem later on, certainly add as many as you need.
Welcome again Rhino. Very cool having another Nebraskan here. We have quite the contingency and I think you'll learn a lot, just like we have.
