Thinking of converting to a home theater setup

Here's how I see it...
First, yes, you've obiously got some gear you've appreciated over the years,for 2 channel dubties, fine.
However, making a competent multi-channel system work is another store really.
It sounds to me like you'd like to keep your sonic integrity for 2 channel in tact, maybe toying with the idea of integrating "more stuff" into your existing. If you go this route, I'd recommend staying with a 2 channel system, adding an outboard modest DD/DTS pre/pro (looped into an auxilary or tape loop on your CJ), and get a powered subwoofer! This still yields a very good sonic experience for movies and music IME! And it's done by audiophiles by the boat-loads full. (you need a pre/pro and a sub, bare minimum for movies to sound dynamic, and not flat).
I WOULD NOT HOWEVER, if you decide to keep your exising gear, try to integrated MISMATCHED SPEAKERS (even from same manufacture) with what you've got! This is a sonic disaster, poorly coherent, and unbelieveable sonic pressentation for multichannel at best!
If you wouldn't use a different left and right speaker, don't mismatch the other speakers as well!!!
The other alternative is to start over with your speakers.(ditch the 2.2's) You can then get matching Thiels all around (keeping your Thiel dream alive!), or whatever, get another amp for the speakers, a sub, a pre/pro(maybe keep your CJ if you want, and loop the AV pre into that for movies/multi-channel dubties), and DO IT RIGHT!!!
FOR GOD'S SAKES MAN,...DO IT RIGHT!!!!...lol
Anyway, depending on your room setup/acoustics, you've got speaker "genre" options. Dappolito's (MC1's???) if you sit far away, or have low ceilings(poor acoustics), typical speakers are ok if you sit closer, or have good acoustics. Multi-driver configs are more solid, less distortion, more coherent when the DD/DTS action gets "heavy/hot", etc.
Otherwise, look for used 2.3's, or 1.6's, even powerpoints (last resort), new, 2.4's
Good luck...from a former Thiel owner myself...

You have some very nice gear! At one point I thought of converting my two channel system into a 5.1 surround. Like yourself, all I would need is a preamp/processor and a 3 channel power amp. Already had a good subwoofer, center & surround speakers (all of the same brand). Unfortunately the preamp processor will not sound as good as a two channel preamp for music unless you intend on adding just a processor to the CJ PFR. What I wound up doing is buying a 6.1 Sony ES receiver which is used for movies only and leaving the two channel stereo for music. Both the two channel amp and Sony receiver share the two front speakers and either unit can be switched in by a high quality source selector, all the other surround & center speakers have a direct connection to the Sony receiver. This is just an alternative. For yourself I would at least keep the 3 front speakers the same brand. I don't know if CJ makes a 3 channel amp (it is usually preferable to try and keep the amps the same brand) but from what I understand the Thiels are power hungry speakers and require a alot of juice. The Krell could be an excellent choice.