It seems to me like the HELOC would be better for short term usage, such as repairs on properties, or flips, but less optimal than a traditional mortgage for long term buy and holds. 

Diego Martinez what are the properties worth is perfect condition (ARV) and what are the repairs?

I have been on the buyer end of things for an FHA loan and it almost fell apart because of repairs that had to be made to meet FHA standards which wouldn't have been an issue if it was  conventional loan. 

But I just have a few questions and concerns about contracts, how to market effectively to sellers, how to know what repair cost will be for damged houses, and etc.

Find a partner and bring them the deal, take a tiny cut, learn from them and actively repair your credit.

The issue that we’re having is not having the funds to get the property repaired.

You should take some time to read some books and analyze the market you will be investing in.Some books I would recommendCrushing it in Apartments and commercial real estate by Brian MurrayRich Dad, Poor Dad by Robert KiyosakiThe One Thing by Gary KellerThe Millionaire Real Estate Investor by Gary KellerOn your first flip - I would suggesting hiring a contractor to oversea the whole procedure.

Tenant is responsible for care, repairs, and maintenance. 

If my investor is flipping the property I always make sure I include the resale costs in order to have a more accurate bottom line number.We also always add 5k to 10k for misc repairs just in case. 

The only way you can be that 'daring' is if you REALLY know your market, repair costs, ARV, financing and closing procedures.