My wife is on board with investing, but we have improvements to our own home we need to do, which we would need to also use the HELOC for. 

You might have to "buy" credibility by jumping on-board with a well-known syndicator/educator.With 250k, that might eat up too much of your capital, so if you don't have a built-in network, I'd go it alone.

The Owner of the property is on board and I have spoken to both parties via phone.

Be advised that establishing an institutional account for your LLC can take considerably longer than an individual account - Coinbase is running about 4-6 weeks for onboarding institutional accounts currently, as an example.The LLC may choose exchange provided storage, 3rd party cloud/desktop wallets, or hardware wallets. 

Furthermore, you are right- without an architect on board you have no idea what all the work will cost nor what or how it should comply.

My goal in the future is multi-family, but currently my husband is not completely on board (he hasn't said that, but I can tell he's less than enthused with my REI aspirations--he's skeptical). 

Doesn't seem like there is much interest from agents or property managers to get on board with another client, am I taking the wrong approach to this? 

It is infectious, and I would bet Dad would soon be on board with your line of thinking. 

Account Closed is to get a local architect on-board, and yes as Mike said, contact a few and make sure they deal with single family home renovations.

He was on board and hired me.