I'm currently getting quotes from contractors and general contractors. 

Depending on the price of the total deal, you should be able to develop the other 2 new builds for about $65psf-$75psf with a good contractor.

Value can increase via no rent increases if the industry is going through cap rate compression (dropping cap rate will raise value price).5 yr term baloon is almost always killer as in this case.  7 yr better, 10 yr is best.The todo in seller financed deals:- Increase value via increased NOI and hopefully enjoy free increases from industry cap rate compressoin so that when you apply for refinancing, the appraisal will come back so that the LTV being offered (70%, 75% maybe 80%) will cover the balance on the sellers note. 

Will I be likely to face lawsuits and liens related to the work done by the auction buyer and his contractors (the lien period won't close for a few months.) 

Admittedly I'm a recent transplant from MI so still feel the newb factor, however been enjoying VT, the area & it's people really well thus far. 

I enjoy good company of friends and family, outdoors and learning new things.

There are 2 possibilities, 1) you hired a small time PM company and they are upcharging you or they just dont know what they are doing and didnt get bids from other contractors. 2) You hired a big firm and they use a commercial landscaping company that charges more because the PM company is a commercial client. 

If you are a realtor, property manager, or contractor in one of these locations please reach out as well.

I understand that a lot of investors just use general contractors or their own expertise, but I am curious if maybe something like same day home inspections would be helpful, since some deals can get snatched quickly?

I think you should ask the seller last time what does it take ($) to sign the contract or you can tell her best you can do is offer say $60K with quick closing as condition.