Should we focus on rapidly growing our cash, or "seed" as I call it, and try to do wholesale deals and fix-and-flips and grow our seed to a much larger amount before buying rentals, or should we invest all of our "seed" now and buy and hold rental property and focus on cash flow and appreciation on that house?

It would release some good seed money but kill a perfectly good asset that would generate cashflow (my goal is staple passive cashflow).

Some principle as a 401k plan, the more you use for seeding in the beginning, the faster your investment will grow. 

I'd do whatever I could to keep her comfortable, these errors can visit me in my old age when I may be vulnerable and I would not want that seed planted.

The faster way would be to flip your cash (or cash like substances) into larger cash, then use the profits (after you've grown your seed money) ONLY to buy your hold properties. 

Ultimately you can turn that cash acquisition into a mortgage, solving the aforementioned problems, but you still need the seed money up front.Rehab-to-perm loans solve this problem. 

Old houses have deep seeded problems, if you have a small project be prepared for it to turn into a large project!

Basically, I’ve been planting seeds for the last few years.

I would rather leave a good lasting impression with a potential future customer rather than sow the seeds of greed.Please don't sell him back the contract to his home.

However, when discussing saving seed money/down payments with her she starts to become a little defensive about our current position.