I can try and answer a few of your questions, I am a non-op MtF. I started my transition about a year ago and am on hormones and living full time as female. At some point I plan to get an orchiectomy but I do not need srs to be happy. There are plenty of other non-op transgender females that simply take hormones and live as girls.
After being on hormones for a year I can say that my sex drive has been reduced, but that doesn't mean I can't get turned on. It may not be the same for everyone, but I have no problem getting erections if I am turned on and it is still possible to penetrate others. I think orgasms feel way better now than they did before I started hormones. For me they are more drawn out and slowly taper off, rather than a burst of pleasure that only lasts a few seconds. I think it has to do with both the hormones, and the fact that I am in a role that I feel much more comfortable in.
I identify as lesbian, I am attracted to women, wether or not they are cis-gendered, MtF pre/post-op, or non-op.