What is the MT3 collet set for? It it's for the benchtop lathes I recommend moving to a 5c collet chuck instead of the MT3 spindle, as 5c collets allow for sticking stock out the back of the lathe.
I'm not sure you need R8 endmill holders either, as the Bridgeport-style mill you're looking at isn't going to be able to take more than a collet's load anyway. However, a pneumatic toolchager is fantastic for shorter students or just for convenience. It makes using the mill faster than walking over to the drill press.
You'll want vise and table-mount stops for your mill too for milling identical parts.
I generally look for deals on Ebay for non-precision stuff like clamps and stops.
If you buy benchtop mills, make sure they are not round-column. Dovetail column is practically a must due to numerous problems with moving round-columns up and down.
I would skip the horizontal bandsaw if you are already getting bandsaws and a miter saw. The latter two cover all your bases. Miter saws are easier to set up imo as well.
As far as edge finder I use manual, as they are cheap and repeatable. Electronics, while more expensive to be as good, are easier to use.
EDIT: make sure you do get a good indicator though for squaring up your spindle and table and centering holes.
End mills from closing machine shops and the like are my go-to (retired machinists also have good stock) but I highly recommend buying a carbide insert face mill for really nice finishes.
We have a Brown and Sharpe 6" for normal stuff and a 12" Mitutoyo for long stuff. I like both brands, and I think anything will work as long as it's reputable. Used Mitutoyos are really cheap on Ebay, but Brown and Sharpe are more expensive even used. Depending on the precision you're looking for used might be ok.
Dial calipers are easier to get a good measurement out of than digitals for me, as I can see the needle move to the "true" measurement.
I'm not sure you even need micrometers, as they are difficult to read and are usually overkill for FRC. However, a digital 0-1" Mitutoyo is only $40 used, and reads dead-on for shaft diameters.
A quiet air compressor lets people talk while working. I had to work with a really loud one for a couple years, and switching to a quiet one was an immense change.