High Speed Sync Question

Hello NS,

So I've been dabling in the world of speedlight portraits lately and I had a buddy sell me 2 shitty 3rd brand speedlites (neewer tt520) for 10 bucks.

Right now I am triggering them from my t3i just by using them as slaves and turning the onboard flashes compensation on but this is only so good.

I really want to be able to do some of the dramatic shots where (using high speed sync) you underexpose the ambient lighting then use flash to make the subject pop.

Here are my questions:

1. If I invested in a nicer Canon flash with ettl and hish speed sync, when I used high speed sync would my 3rd party shitty speedlites work as slaves?

2. Whats the cheapest higher end flash I could get that would have ettl and hss? And what is the cheapest (but long) wire I could get to trigger it? (I've ruled out pocketwizard kind of things because of the price)

Thank you,

Louis