#1
Aight well i got a bass thats slightly heavier up top where the neck meets the body an my bass tends to lean towards the floor(neck down) anybody got a suggestion for a nice strap to keep my bass aimed upwards?
#2
I'd recommend either Dimarzio Straploks which i have an 2 of my guitars, or Planet Waves which I have on my Jackson V. The Straploks replace the actual strap buttons, so if you're not comfortable with screwing the strap directly onto the guitar I'd highly recommend any of the Planet Waves straps. Mine hasn't once come off.
#3
^That isn't what he's asking about.

Try to get a strap with a leather part underneath (so the leather part is touching your body). That way, when you play with your shirt off, the bass will stay in place. But if you're wearing a shirt, then there's really nothing much you could do to keep the bass upright, beside maybe hanging a type of weight on the body of the guitar.
WHY IS EVERYONE IN THE PIT A FUCKING METALCORE KID
#4
A thick and nice leather strap should solve most of the things you mentioned.

Or the good ol' method of tying bricks to the other end.