How do I connect alligator clips to an AGM battery for CPAP?

Other question I have (I know, I am annoying with so many questions):

1. Do the eyelet terminals of all AGM battery match the size of the eyelet terminals of all battery chargers?

2. If so, what size bolt do I need? Are these available online? And do I need a nut and washer too, or are the eyelet terminals pre-threaded? The bolts at places like Home Depot are in sealed plastic, so I will not be able to see if they fit.

3. If I charge my cell phone at night on the same AGM battery as the CPAP, will that cause the battery to drain a lot? Or should I use a separate battery for the cell phone?

4. If I buy a buy a battery case, like below, can I split the wire coming out of it to charge a phone as well, or do I need a fancy box with a USB outlet already built in?


5. What fitment group are 35 AH AGM batteries in? U1?