I need help owner financing

ok, i have been living in rental for 3 yrs. my mo. is $2900. in california

house is fmv around $900k

I am only going to live here for 18 more months.

Am I crazy? owner has about a $100k basis–inheritance…

How could I structure a deal to keep my payment at $2900,—do some improvements on my own, and then sell in 18 mo. and split profits with seller? somehow helping them with tax consequences?

ok, is the following even possible.

can owner sell to me for $400k, I get 1st for that.

and then we have agreement in 18 mo when I sell that
they would get first $500k

and we would split 50-50 on profit above

What price is he willing to sell it for? Why would he take 500K if it is worth 900K? Need more info to understand your question.

So you want to sell in the future, give him $900k in total, and hope it appreciates above that so you will be able to keep half of the proceeds in excess of $900k? With the CA market adjusting back to reality at this point what makes you think it will be worth more than $900k in 18 months? Speculation at best.