Financing Rehab for First Deal and Other Beginner Questions

[Curtis Regan]

Hey Everyone!

My wife and I just put an offer in to purchase our first property. It is a duplex with a tenant in one side and we would be moving into the other side. Both sides are 2 bed/1 bath with an 800sf unfinished basement on both sides. My plan is to finish the basement and add a bedroom and possibly a bathroom. I've gotten approval from the city to make these additions. 

We currently do not have a lot of cash saved up and are looking to use an FHA loan with 3.5% down. After that we will only have a few thousand available for the rehab costs. I've gotten a few bids and estimated the rehab to be about $20k/side. My question is, what are some options for financing the rehab? The options I've considered are a 203k loan, a construction loan through the bank, or a home improvement credit card with 18 months interest free financing. Currently I am leaning towards the home improvement card as I plan to refinance out of the deal once the improvements are complete. Does that make sense to use the credit card and refinance my mortgage within the 18 month interest free time period to pay the card off? Are there any other rehab financing options anyone has used?

Thank you all in advance and I look forward to discussing this further!