As I understand it, you would need a Sonos Bridge - AND a Sonos Connect:Amp. Def Tech speakers are quite sensitive so this should put out enough power for them - the reviews on Amazon indicate people using all kinds of speakers and getting good results.
Is it impossible to run speaker wires from your AVR to the patio. It was a pain for me as well, but it only cost the price of a spool of wire and once done I didn't have any other components - just my AVR and another pair of remote speakers.
2-Ch (HT L/R): Oppo BDP-105 BD, Adcom GFP-750 pre, Bryston 10B Sub Xover, Bryston 4BSST2, Paradigm Signature S4 v.2, (2) SVS SB12-NSD subs, AQ & Cardas XLR
Home Theater: Bryston 4BSST2 amp / Paradigm CC-590 (C), Outlaw 7700 amp / (4) Def Tech UIW-RSSII (LS/RS/LB/RB), Samsung 46” 3D LCD