Yes.
Not really.
The problem isn't with getting power to everything, but the data signals wouldn't be connected as you're talking about power adapter ends only.
Now if the SATA connection is via a 3rd party SATA card, then you could just string various power adapters together, and run a SATA cable from the card to the SSD. Unfortunately, you'll likely have issues getting one that will boot OS X (presume you don't already have one that does).
Making your own adapter:
There are easy ways to connect the wires, so there's no need to panic. Wire nuts, crimp connectors (butt splice; pic is for illustration - you can twist 2 wires together for one end, and use a single wire in the other <cut this end longer, and fold it over so it crimps properly> - I'd recommend using the blue one if you go this route) are a couple of ways. The reason for folding the wire, is the gauge is likely too small for blue (expect the adapter wiring will be 18 AWG, and blue is meant for 16-14AWG).
Another, and easier method, is to use tap splices (no cutting of the wires on the Backplane Extension cable at all; downside is they're bulkier once you get it all assembled).
You should be able to find these connectors locally with little to no hassle (i.e. auto parts or hardware stores carry them).
BTW, you'll want a pair of crimp pliers if you use butt splices (additional information in the link, which I'd recommend reading).
Yes.
Take a look at this article, as it has some performance data on the GT120.
