I've been visiting the board for a while, but this is my first time posting. I'll give my humble input.
Of the speakers listed, I own the Vipers, CDT CL's, CDT coaxials, and US Acoustics 4065 (among other amps).
Suggestions--
Front stage: CDT CL's or Vipers. Imho, you can't go wrong with either one. CDT's are a little easier to install.
Amp: So many, but I use DEI and US Acoustics. Both have proven to be good brands. I hear Avionxx is also good.
Rear fill: In a subless system, you want to give extra attention to your up front bass. To do that, it's best to have no highs coming behind you. I would either put the CDT CL MIDS (
http://www.thezeb.com sales them separately) in the rear. They have great midbass and won't have too many highs. Even better, go with Bulldogs suggestion about the Tang Band 6x9. They are 8ohm so the hu won't push them. You'll need amp power. But those look like they could be used as mini-subs.
I would look into the Tang Bands myself, but I already have some Vifa PL 7" mids that put out crazy midbass. I'm going to be setting those up in a subless system that uses CDT CL mids up front.
Side note: For the REALLY budget minded, CDT coaxials up front and CDT mids or Tang Band's in back, all amped, would still be a good budget setup.
Hope all goes well.