Ditto to all of the above.  85% is very doable with a strong credit score, strong dscr, but yes, the rate is going to be higher because of the higher leverage.

The cost to do so was 50k to join.

You don’t have to use it like short-term debt—you can pull from it strategically and pay it back at your own pace.

Welcome to BP @Nathan Deutsch!

If I see a property on the MLS and I want to offer seller financing (or use creative financing strategies to fund the deal), do listing agents quickly disregard these offers?

If the HELOC rate gets out of hand, then go to the bank at that time.

Most builders don't sell to investors.#3. 

Therefore, you don't need to use a 1031 exchange; you can take as long as you wish to find and then buy another property.The only exception is if there is debt on a property, in which case there will be some UBIT (Unrelated Business Income Tax) implications.

Feel free to reach out with any questions.

Be sure to explore all around the forums as well as many of the FREE tools that Bigger Pockets provides.I am on the lending side of things and am always happy to hop on a call to discuss loan options that are out there, even if not offered by my resources.