My little niche

I have a 2.5 year old daughter who is not a fan of the whole grooming thing. :) We've worked through getting her to brush her teeth and hair every day at home, but when we go out to the professionals, it's a nightmare. The dentist is used to the headstrong ones, so he has us book a special appointment at the end of the day and my husband and I go so we can assist the hygenist to get her teeth cleaned. (Sorry, clean teeth are not negotiable.)

However, we are just batting zero when it comes to hair cuts. We have taken her to several child salons, and we are just not having any luck. She's fine playing with the toys, but the second it comes for her to get in the chair (or climb onto the four-wheeler), she starts screaming. We have to hold her down to get her hair cut. We have tried talking to her about it before the trim, having her watch her sister getting the cut, etc.. We have given her a lollypop before the cut. She just works herself into such a hissy that she's just so pissed off that we have to just bear through it. 

(Her father used to be like this as a child. I have asked my MIL what she did, and she used to just wait til he was asleep and walk him to barbershops around London. Sometimes, he would get haircuts over two to three days.  Alas, I live in a suburb of Atlanta which is a car-based community and she wakes up easily. :/  She has the same easy to rile personality as her father. Sometimes, I  just glare at him. Lots.)

I have a 5 year old who just loves getting her hair and teeth done. She's such a people pleaser, it's not even funny. The odd thing, she's the one with Sensory Processing Disorder (under-responsive for some input).

Any advice from parents who have been there?