Someone who educates children and their families? Is this someone tutoring individual families in the learners' homes vs. teaching multiple families or children in a classroom environment? By ability and skill level, do you mean in terms of teaching ability/skill or ASL ability/skill?
There's such a continuum possible there. From personal experience:
Family sign in my home: exposure to a Deaf person (or persons) was critical -- we learned more having dinners, lunches interacting with and watching the interactions with and between our teacher and her husband than off the pages of our lesson book. Teaching ability wasn't as important as exposure was: understanding the customs, seeing the fluency possible, establishing a friendship, becoming aware of how a deaf person communicates and seeing the language unfold well beyond learning vocabulary words. Seeing someone make ASL come alive in day to day life. Our family sign instructor was so wonderful, not because of her ability to teach us sign (which she had as well
even though I'm a terrible student), but because of her ability to make a connection with us, without relying on voice or notes, etc. (Yes, sometimes we got into complex issues that required passing our handy notebook back and forth, but even that was a lesson in itself). She's probably horrified at the limits of my signing, but she never makes me feel like a bumbling dope. I mean, I still feel like one, but she's not the one doing it. She's old school Deaf with a whole lot of pain in her heart from her own childhood who might protest CIs vehemently on weekends, but never, never makes me worry that there's anything but love in her heart for my little cyborg. She brought us together with other Deaf families, with other deaf children. She brought the community we didn't know existed to us. Four years later: she teaches at my daughter's school and my daughter adores her (opting to leave her auditory access class every Friday to take part in this teacher's class conducted in ASL-only), she was my daughter's first choice for her very 1st videophone call and we happen to be having dinner with this lovely lady and her family tonight after too long
).
I wanted my early ASLI, II, III teachers in classroom environments to be skilled at teaching, able to convey what was to be learned (as opposed to having the depth and breadth of ASL and the ability to wield it in true discourse), because we were just building foundations and I need to know what there is to know at a basic level and get over that hump between learning vocabulary and learning how to use it. I needed someone who signed very precisely, someone who would be watching for comprehension, probing for it, and repeating patiently. More teacher than signer (not sure if that makes sense). Really liked my ASL I/II teacher, very active in Deaf community, made ASL fun, and yet pushed us: she made me feel energized!
At more advanced levels, I want my teachers to have subject area expertise, I'm then directing my own learning -- I need ASL users who are really using the language to its fullest, with great precision, likely native ASL users.