Please help identify

[Madtrucker]

I've been working on my 72 blazer 4x4 and have come across a few things i'm unsure about.

One is a small cylinder mounted under the floor above the rear axle, it has 1 wire going to a toggle on the dash. it's about 1" diameter x about 5" long.

Another is hanging out around the trans area with 2 wires, possibly from the original sm465 trans?

The third thing is an old electric fuel pump still hooked up inline to the mechanical pump. Wouldn't that choke down flow to the mechanical pump, seems that it would have to spin the impellers to pull full through.

I'm sure I'll have plenty more questions as I continue, so thanks in advance.