Re (2) GP 5 you have to Loosen, the Bolts and rotate the Grip,
on the bars to fold it or it wont reach the catch pin, do that ant they are out of the way.

GP 3 you Dont. I've got those on a 2 year old M3L Bike.

never tried the 4.. fit ? Its easy on the new bikes ,7/8" bars. ,
Had a older Mk2, its bar is 15/16 so they didnt fit.

Considering getting the one without the Bar end at all , a bit of the reach around issue,

but I can catch the tip of the brake lever from the Bar end with my fingers ,
(the brake levers are different now, better, many say, )

But its not a powerful grip. a slow down, not a panic stop.

dont own a case. so IDK 1 bolt removes each if there is a packing interference.