who carries suspender pants

They are real and they come with buttons so you can have your own

Do I have to sew buttons on pants

Depends if your pants came with suspender buttons already sewn in. If not then yes, you will have to stich these buttons to your pants yourself. Don't be put off by doing a little needlework, if you can tie a fishing line you can use a needle and thread.

Are they real (not fake P Urethane) leather ends?

They appear to be real leather.

Are they strong enough to hold your pants during daily activities?

I would say absolutely, I put them on a pair of wool hunting pants and had zero issues during hunting season. Walking thru woods, climbing, on average 5 miles per hunt thru woods and never once did I have an issue, great product so far for me. Would buy without hesitation. Simple to use, just poke small hole(I used one of those tiny screwdrivers so hole wasn't to big) in pants where you want them, insert buttons, screw together, Done!