I have a number of heuchera in full sun in zone 6a. But none you listed. Timeless Night is doing very well. I tried Fire Alarm a few times under different conditions and it never overwintered. For a red look see if you run across Monster Mahogany which has done great for me. Others I have in full sun that have done well are Brownies Pinot Noir , Pinot Gris , Caramel, Midnight Rose , Northern Exposure Silver, Encore, Mocha. Frosted Violet and Bronze Wave. All burn a bit at first if I get them from a place that grows them in shady areas , if they were already in sun they do fine.
