#1
ok so im being given some speakers that used to be hooked up to a TV as part of a surround sound system because they wouldve otherwise been thorwn out.

Id like to repurpose them into PA speakers so my band and I can practice with vocals being audible.

I have no idea what in and outs these speakers have, I havent seen them yet but Im gonna try to do this as cheaply as possible.

things i think ill need:

something to amplify the vocals (powered mixer?)
and a mic or 2

as well as whatever various parts and cable id need for the conversion
#2
This is one of those "depends on" questions. It depends on a lot of factors. How large are the speakers themselves? How large are the cabinets? What's the power handling capability? Are they full-range, or something less?

Chances are, they don't have the power handling that you need, aren't designed for PA use and are less than full range.

If you're buying an amplified mixer and the mics, you might as well buy the speakers designed for the purpose, too. Many places sell bundles.
#3
well its nothing too powerful that we need, pretty much to be heard over our instruments in our basement/garage,

if it comes down to it, yea we will probably buy some cheaper PA package off MF or something