USGI surplus bearsuit bibs+cheap rain bibs, or if you have insulated chest waders wear them.
My winter kayaking setup is basically my duck hunting setup>hodgman 5mm neoprene waders with 1600g insulated boots>Banded wader jacket with primaloft liner>Icebreakers neoprene or Browning W+B insulated gloves, depending on weather (the Brownings are warmer and thinner but have a dumb cuff, can't complain for $28 tho)>USGI grid fleece longjohns if cold enough
I've done light current down to -15F and not been miserable. Be aware that pretty much no matter what you WILL be wet in a kayak, the question is whether you'll be so wet you're freezing. You lose a lot of mobility in waders but you're basically completely waterproof from the nipples down so you need to seriously fuck up to be really wet.