Can I still use it for fix and flips or wholesaling?

VERY unlikely unless you either source an off-market property yourself or you find a unicorn deal (our last semi-BRRRR was a B-neighborhood property we sourced from an out of town wholesaler in late 2023, but couldn't get all our capital back out on refi).  

We plan to build a cabin or cabins for our family use and an STR.

or get this sold or is the interest rate too hard to get past? 

BiggerPockets is full of resources designed to help you along your journey, whether you are just getting started or a seasoned investor.

You have NO leverage, no matter what he builds or does not build, except for the developer saving some money in legal fees and cutting down on mesne profits damages.

Gas or electric would be a much better option, safety wise, from a house fire standpoint, CO danger, or danger to children or pets from the open flames. 

I'm not sure if this is a local thing or if it's common in all markets.

I am looking to buy a 2 or 3-unit home in NYC.

One of their so called instructors from one of the training sessions asks the students to go to the five star hotels, or go play golf, or go horse riding, or go hang out at the high end night clubs for the sake of fund raising.