Help me make an album

[Coffee]

I am going to be recording an album sometime in the next three months to a year. I play guitar and sing, but as it turns out, I am writing many of the songs for the album on the piano. I want to make an alternative album with elements of ambient and industrial music.

I have some questions, though. I am planning to do all the singing, guitars, and keys. I can probably do the bass well enough for my purposes. I already know I'll have to get a rhythm section of some sort.
So:

1) What instruments do I need?
2) Do I need keys and regular piano?
3) Do I really need to get a bass player instead of trying to be Lenny Kravitz/Paul McCartney and play everything?
4) Should I get a drummer, or is there a drum machine that is programmable enough/affordable enough to do the job?
5) Should I buy the instruments, or are there decent enough rentals?
5a) If I should buy the instruments, what would be the least expensive studio-worthy brands that I could buy?