I don't even remove my listing from online until I have a signed lease, and their funds have cleared my bank account.

If you are more comfortable with an agent just find one to represent you on the buy side, and pay them out of funds at closing.

I'm working on lining up funding and I would like to put an offer in, but how do I do so, if they aren't responding?

Can you use proof of funds letter instead?

You could have unsecured funding within 2 weeks.

There have been several occasions on deals I've wholesaled where we didn't assign the contract, and we actually closed on the property using a double close, or even transactional funding.

I actually lol every single time I read this under experienceRegardless, the IRR is dependent on many factors including: purchase price, exit price (this factor is the biggest contributor to IRR), rent growth strength, ability to re-position, debt terms - LTV, rate, term, IO years, amortization yearsArticles you might find useful:The Inside Track to Vetting A Multifamily Deal SponsorDeal Screening Checklist for Passive Multifamily InvestorsFocus on developing relationships with the right syndicators (full disclosure: I am one) with the right background/experience working with the right teams. 

Creative Funding?

I’m looking for creative financing to fund the property’s down payment.

Basically the same as conventional loans....ltv‘s of 75/80%, similar DTI’s, etc., if you can gat get 30 year loans.