I have been very happy to find the Alsdorf line are quite cold hardy here is SE PA (winters milder than some of you, I realize). They have both single and rose comb in the genes, but the single combs are smaller, like a Welsummer, and not large like a Leghorn.
I have not had any problems with hens picking on males. I lose some birds that just fail to thrive and sort of waste away. I had assumed Marek's, but most of my birds are now vaccinated and I still see it some. I don't "coddle" my birds, they have to survive on a farm with minimal care beyond what a regular chicken would receive. I raise a lot of young ones every year to allow for me to lose up to half and still come into spring with a good sized flock.
I don't try to breed for a particular color pattern, but my personal favorites are the blonde (Crele, Cree, or whatever), so the males in my breeding pen are all that color. I believe that the grizzly colors are larger birds than the crele, but have not weighed them to check that, it just seems that the crele are a bit smaller and shorter. I would not mind if the crele birds trended to bantam size, they would certainly be fine pets even if small. But I am not actively striving for that, my main goal is maintaining a wide gene pool for a long time. If I had the space for 2 pens, I would separate them into 2 lines, but I would rather keep 1 larger pen and reserve the small pens for breeding experiments with other "laying type" breeds (currently working with sex-linked black/lavender Ameraucanas and Isabel Welbars/Welsummers/Olive Eggers).