I'm wondering if my staining is going to be uneven now that I used 150 to get rid of a few swirls
and so forth? Should I go buy some 80 grit discs and go over those spots?

thanks in advance!!

The entire floor must be sanded exactly to the same degree if you expect the stain to be uniform.
One of the biggest influences on stain colour is the grit of paper used to prepare the wood. Of course, there are other factors that will affect the stain but this is in my opinion, the biggest. The smoother the wood, the lighter the stain, which is why we will often "water-pop" the floor prior to staining to allow greater penetration of the stain and to deepen the colour.

Thanks Dennis, I appreciate it!
Hopefully all the help I've received over the past week here will help a lot of the 1st timers that
are tackling this and have the same experiences I'm having.

Fortunately I have time on my side, no wife or kids to squawk at me to hurry up.
Only 2 cats that act like feline dustmops .

SO........In theory, you could (after the big post-edger/drum 80-Screening) use several different means
to sand touchups, (palm, orbital, hand, block etc etc) and as long as everything is 80 I should be alright then?

It's been a great experience! Hard as hell but whereas most people would have rushed into the stain I'm able to examine
and learn new things as I go along and will be disapointed when I'm all done!