Gas lines are determined by your design. Beverage length depends on hose ID, serving pressure, and temperature. I used to use ~12' of 1/4" per tap at 12psi and 42F, but now use barrier tubing which has more complex resistance calculations. You'll need ~3-4x as much line for soda since it's under higher pressure.
Shank length is once again best determined by the keezer design. As you already pointed out, longer helps somewhat with foam control.
You'll need sankey couplers in order to serve out of sankey kegs, although bevmo might rent them. You may also want to look into a conversion kit that has the MFL fittings so that you can quickly and easily switch back and forth between sankeys and cornies.
Temp controllers are a personal preference. I have a couple digital rancos that are nice plug and play, and a couple of the e-bay temp controllers that are cheaper and work well but require some wiring.
It sounds like you already know your options for regulators and manifolds and just need to make a decision. I used $2 harbor freight manifolds and a single reg for a long time, and later added a secondary.
Originally Posted by ZamaMan
is there anything Im forgeting?
Tailpieces to fit your tubing and tailpiece nuts? Shank nuts if they're not included with the shanks?