Please help me learn what these are?

[RubiRidge]

1986 K5 Blazer Silverado. Originally had 305, now has 350.

1st pic. comes out from the drivers side went under the carpet and connects behind the panel that conceals the seat belt mount.

2nd pic. dead center of the engine bay. i have not seen its female connector

3rd pic. originally under the headliner, the one on the far left in the picture appears to be a radio antenna and is a larger gauge wire than the other two. The other two are identical in gauge. All three are connected to some sort of mount on top of the cab. The mounts are all three identical.

4th pic. hose and connector that are taped together coming out of the firewall just beneath the junction box

5th pic. Small gauge black wire that was cut but had an identical piece less than an inch away that was grounded to the body under the drivers seat. I have replaced the connector on it and secured it out of the way. I do not know what it grounds.

Thank you for any assistance you may give. I do not know very much about wiring and electronics for automotives, other than common things such as how to test for hot vs ground and how to use a mulitmeter.