Re: Does My Deed, Paid Land Survey and City Hall Documents "Hold Any Water"
Assuming that your surveyor properly marked the correct lines, and I have no reason to think that the survey was performed incorrectly, then your neighbor has an issue with her builder and possibly with her title insurance carrier, depending upon what her policy covers and how it's written.
It seems that up until the time of your survey, you had each been living by the belief that the line between you was in some location that accommodated all of her improvements. You might consider selling her a strip of your land so that her drive, gardens, and whatever else would be on her property. Hopefully for her, she could get reimbursed for it by either her title insurer or her builder. The only potential snag to that is that the builder might be able to weasel out of his liability if this has gone beyond the statute of limitations for claims resulting from negligence. I can't recall if MI has a strict statute of limitations or if that clock begins ticking when the negligence was discovered or should have been discovered.
Anyway, unless you have your heart set on some particular use of that newfound additional property, that since you've each been living peacably under a different belief, you might be able to adjust your boundaries (with appropriate compensation to you, of course) to a location roughly where you previously believed the line to be. This solution would avoid your neighbor having to remove or modify improvements, would avoid you having the encumbrances of another's use of your property for the existence of their improvements (even if permissive), avoids potential future confrontation over real or claimed property rights between you and your neighbor or successors in interest, avoids the potential for costly litigation, hopefully leaves each of you with a lot configuration you can each find acceptable at a price you each feel is fair, and most importantly preserves the peaceful and neighborly relationship.
I'm a surveyor, not your surveyor & not an attorney.
Advice is general survey, not legal. Hire a local professional for specific advice.