It’s basically an unlimited contribution Roth, with tax free borrowing. 

If you have a business entity(you want to properly track money going in / out from its owners).They will likely be classified as contributions / distributions.Best of luck!

How much time / cash / other are each individual expected to contribute?

The way I'm looking at it, if my spouse and I only do employer matching for the 10 years we would have more than enough in there and still 10 years out from being able to access it.I do plan on doing 401k loans for deals if the numbers check out, and I've considered rolling over some of our 401ks into roth IRAs to access our contributions but we'd have to pay taxes out of pocket (a big hit to cash flow) and we couldn't touch it for 5 years.  

If so, simply put more down or consider the month to month an additional contribution capital wise.

Thanks for contributing to the BP community. 

I look forward to engaging with you all, sharing insights, and hopefully contributing to discussions as I progress on my journey. 

Also contributing to this rise, damaged homes from Hurricane Helene.

i think both parties have contributed.  

Any transaction done with little or no equity contribution is most probably (there may be a few exceptions) in danger of “blowing up” from over leverage and insufficient equity cushion.