The tight spaces you can reach with this adapter is very tight. You need about an inch worth of spaces.
Interesting question; the package said "up to 30x life" but I don't remember an explicit warranty. I believe that Milwaukee has a 1 year defect warranty on their tools, and I know they are pretty responsive if you contact them.
You have to pull hard; the magnet holds it in tight.
it is a standard hex fitting
it is hex drive
I’m sure it would work for a couple but over time it’s going to destroy it. I have had self feeding spade bit twist where it goes into the chuck of a drill using it normally so adding the 90 degree adapter is just putting more parts inline and I have yet to see any of these type of adaptor a hold up over time. So far the Milwaukee seems to be the best built but I wouldn’t use it for hole in that size unless I had no other choice and would only do it once or twice.
Yes, to hold in bit, but not strong enough to hold screw.
I used an m18 impact with no issues so I think you should be fine