Thanks for the add'l info. I wouldn't worry too much about the speakers outclassing the components. As long as the amp puts out adequate power to drive a pair without distortion or clipping, your in business. Besides things may change and you may upgrade the amp some day. Since speakers are usually the most expensive item in a system, it is easier and cheaper to upgrade electronics later. So I am a believer in getting the best pair of speakers you can afford now.
That being said, I still contend that you should be looking at 8 Ohm speakers with a higher sensitivity rating. Using stands, about a foot and a half from the rear walls, will allow you to look at either front or rear ported. I would suggest you check out the Focal 806V and 807V's that are 8 ohms at 90/92 db sensitivity respectively. That makes them very efficient with lower wattage amps, front ported so you don't need to worry if you only get a foot from the back wall and should sound very nice for acoustic and vocals. Maybe a tad forward though for jazz.
If you really want a bargain, that should work on all counts, check out this link for the Focal Profile 908's.
http://www.musicdirect.com/p-83551-focal-profile-908-diamond-black-pr.aspx
Hope this helps in your search.