if you option drag it to 8 bars from 32.5 its going to be really fast. You're better off making an 8 bar loop by:
1) ignore the tempo of the track, an dcount 8 bars of the sample
2) create a loop of the sample then adjust it until it loops perfectly, then cut it using the loop locaters as a guide
3) option drag the new region to fit 8 bars according to the tempo of the song.
Sometimes I bounce the region inplace before I loop and cut it - some samples don't like to be option dragged until you bounce them.
I don't know why you can't use time and pitch machine - are they audio regions? do you have the sample editor open? i dont' know if i can help here, maybe someone else can step in?
Q 3: Yes you can use single hit samples in Ultrabeat. I really recommend Steve H's Ultrabeat tutorial:
Logic 204 Ultrabeat Unleashed [url]https://www.macprovideo.com/tutorial/logic9204[/url]
It totally explains how. There is a really good load sample feature that allows you to add any sample you like, and manipulate it in a number of different ways.
Hope that helps, let us know how you get on!