After closing, her estimates is now at 100k for the rehab alone and her project management fee.She wants 15% of total project (which I kind of want to see if this is reasonable?)

Who is doing the work & the anticipated quality of finishes is needed to give a rough estimate.

Not sure how accurate this is across the market and different types of properties, but I have found $10-$12 a SF to be a good estimator of what it should cost to furnish and decorate an STR.

I would be getting estimates for electrical for 3 additional meters as opposed to ever considering having utilities in my name.

Quick estimates for BRRRR and whether they will cash flow in the future should be based upon the future debt service you anticipate you will have on the property, because that will be a big factor for determining your cash flow.

Other than the sentimental value of a home and the chance of equity and resale value we could really do without purchasing one. 

Chances are, however, that tenants will only agree to it if it benefits them (reduction in rent, extension of the lease term at the same rent, etc.).

I will try to get an estimate to rebuild the detached garage and cover it accordingly 

The chances of them protecting your best interests is slim. 

Similar to these folks points - I think you want to be conservative on vacancy rate estimates and maintenance costs just because you'll see more unit turns in that area.