Sounds like it is effecting the lenders collateral and thats why they don't want to do it . should confirm though 

Basic recommendations- Deed of Trust-Personal Guarantee-Promissory note-JV agreement (to protect the lender from violating usury laws)-clear late fee schedule, cure period agreement-cross collateral if the subject property doesn't safely cover you with enough equity

If you indeed want to just be involved in the deal and thus want your piece of the pie too, then it would be approached as a regular transaction where you're only owning 25% of the property and thus the lender would collateralize your portion of the asset. 

Farm ground they will only collateralize at 65%.  

If you are a developer and plan to tear down the house and do something else with the property then you wont be able to get a residential loan because you are going to tear down the bank's collateral and then do something else which is definitely against the rules. 

Failure to maintain adequate insurance puts your collateral at risk and is a big deal, @Jay Chekansky.

That's primarily due to the collateral that is the policy death benefit....low risk for the insurer because they know, eventually, you'll die and they'll recoup the outstanding loan before paying out the death benefit.

Obviously I know I will need to pay this back ASAP which can be risky using my primary as collateral, and I don't think I can qualify for another HELOC/HELOAN from the Condo because of my $18,000 debt, right??  

Take a loan out to do your project, use your bank investments as collateral.  

Unsecured (no real estate as collateral) is not a great way to lend nor is secured loans with no equity to protect your principal investment.