You have allowed it to get this far, by not dealing with all of the smaller things you listed at first.
Soon however she began to order me around like I was her groom, 'teach me' about things that my boss was teaching me to do correctly, and even interrupting my dressage instructor who came out to tell her how to teach me. Many times when I was fixing fencing in an empty field she would turn horses out and then proceed to stand over me as I did my job, like I'm a devious person out to maim horses. When I would bring up my gelding (who's spooky and isn't really a fan of new people at first) she would do 'pressure points' to 'ease' his worrying without my consent and ignore my 'no's..... and freaked him out so bad I couldn't get him into the barn easily for a few weeks. Whenever I ride she would come over, and instruct me on what I was doing wrong (for instance my mare doesn't cue with any leg, she hates it) and verbally berate me for being cruel and immature with my riding.
You are allowing her to walk all over you, and that's one thing, but when she brought up your gelding and put her hands on him, you needed to stop that right then and there. If you choose to allow her to treat you badly, that's one thing, but she shouldn't be putting her hands on your horse, and it's your responsibility to protect your horse.
As you allowed all of this, then she's the type to think she can work your horse.
I went out a few weeks later and saw the lady out there working a horse in the roundpen using her natural horsemanship. I didn't think two things of it and was going into the barn to sit while my mom went and got my mare when I poked my head out the door to see her working our gelding (the skittish horse). He was dripping in sweat and my mom gave her a talking to and brought him up.
and what did you do? Why didn't you see it was your horse being worked as you drove in?
If she had put her hands on my horse or worked him, she would have been finding her teeth in the toilet bowl the next day, after she passed them.