My question is how do I make sure I can refinance the property in the 2 year window that the seller is willing to carry.

However, it depends where you both are on your risk-tolerance for taking on additional debts while you have student loans that have to be paid no matter what.

Then again it might be worth it to you to build up a solid business relationship with this particular contractor but it seems to me he is already reducing his risks since you are paying for his labor.

Especially with the risk of breaking the plumbing. 

From everyone I've talked to, they very rarely get called in these circumstances, but I decided I was willing to take that risk.

Although an investor in your jurisdiction might have experience with similar actions, to get the best up-to-date information (and save others the risks of unlicensed practice of law) you're best off talking with an experienced real estate attorney barred in the appropriate jurisdiction. 

I see that they are more expensive, but I would consider doing that before I put capital at risk.

I would want to know more about what your goals are and specific risk tolerances but feel free to reach out to me directly and I would be happy to discuss my thoughts.

I can't imagine neighborhoods are at risk with someone Airbnbing their house or apartment or basement. 

Here are some ways you can raise capital: 1) You can raise money through your family and friends, 2) seek a private money loan, 3) syndicate or joint venture the deal, or 4) ask the seller to carry the financing.With the seller finance option, you may still need to bring in a down payment, as it depends on how you negotiate with the seller.Where to raise capital is pretty important but how you structure your deal to entice investors to want to take part in your deal is equally important.