I have seen two menalistic deer and one piebald
Although not super common, there are in decent numbers in hays, Comal and Kendall as well as a few other counties
No they are not, but certain parts of the hill country have pockets with fair numbers. Most hunters I've known have passed on them to try to protect the few out there. They are an oddity and make for interesting conversation.
Myself as well as others have passed on melanistic deer as well as one solid white doe we had on one ranch I hunted.
That white deer was spooky. You'd be walking to your stand in moonlight and have that doe standing just a few yards ahead that would get you to jump way before the deer did. Also it would scare you when it ran out in front of the headlights as you drove down the pasture road.