I tried getting it from a credit card.

Say if I were to win the auction and get an acceptance from the bank on my bid/offer, do I become responsible for it? 

All your suggestions should allow for a win/win in this situation.  

Dealing with tax lien certificates, once you win the property and are past the redemption period, you are also responsible for foreclosing on the original owners to acquire the deed, then a quiet title action so you can get title insurance.

I have struggle to find 30 yr fixed after my 4th property so I consider this a big win. 

Seems like the latter would be a win win.

So now 5 months later with at least 2 more to go, you are out 5 months of rent, $7,000 in legal bills (and counting-we are not even at trial at this point) and by the way, if the tenant wins their case, the insurance company probably will not cover the judgement as it is excluded in the policy.Also, if the tenant decides to call code enforcement and they find mold, now you have to remediate professionally (again not covered by insurance) and it will cost you about $15,000 or more because they have to do the whole building to kill all the mold.Oh, and by the way, the tenant called code enforcement and there is no visual mold but all this is going on anyway.So legally, you may not have to but it will cost you a lot of money when you get a tenant who can play the system.Make the attempt to fix it so you can say you did.Tom

Total investment of my own money is $25k, however I have borrowed $55k at 8.5% interest only through a private lender, and have another $30k between (2) 0% credit cards. 

#3 -  put $500 in yellow cards and look for motivated sellers/ wholesale.?

Don't forget that as a Bigger Pockets member you get a 10% Discount.I would send a six month campaign starting with small text Postcards, then Yellow Letters, followed by Large Text Postcards, then a Professional Letter, Greeting Card and finished with a ZipLetter.