I signed a year lease with the tenant already and the management suggested that i extend the lease to a two year.

Something similar to the attached.

Welcome to the community

Overall though, if it's a private loan and not a hard money loan, other than the costs of the loan itself (interest rate, points, etc.) the costs should be pretty modest. 

We are getting a sofa bed for the living room of our STR.

However, the one constant in these emails is a request for the broker fee co-op and determining the offered co-op fee seems to be the motivation behind these emails.

If you're actually correct and the village has a 59k assessement on the land but the reality is the land is worth 20k, then I'd consider getting an appraiser even. 

I've heard they are the best on the market and that they have pretty reasonable pricing.

It's also very important to know the wants/needs/position of your buying audience.I find that buyers are much more willing to get into a bidding war, and over bid on a property as opposed to paying their buyers agent.

look at other STR data in the area and do similar style to do your best to recreate similar results