@Kahren Aydinyan I've never seen a clause that says you MUST refi WITH THEM every 5 years. I think you're just talking about a balloon pmt in 5 years, but you should be able to refi with anyone. I doubt that's even legal (to require you go thru them again). With regard to 15, 20 year vs. 30 year, etc. I would lean towards 30 year. Pmts will be less, no need to refi (which will cost you - in one way or another). If you CHOOSE to make additional principal pmt, no pre-payment penalty, but it is your choice to pay it down faster if you want to. Also, keep in mind that if you refi, it DOES cost money (even a "no-cost" refi), and you will probably be adding on to the term and therefore paying more over the cost of the loans you have for the property. If that doesn't make sense, let me know and I'll give some examples.
And my first thought too was what @Jaysen Medhurst said - 68K all in for 70K ARV. BUT, it is a step in getting your first property. It will be a learning experience, and if you can cash flow for $350, that's what makes this project worth doing. With only 2K difference in value, it would be all about cash flow. Just be careful you consider the costs of your loan(s) including refi's. AND the cost of the $ you have tied up in this project that you cannot use to invest elsewhere.