(Full) open slots for a 12 team dynasty SF league through Sleeper

Doing a secondary rookie draft sounds like a good idea, but you should really combine it.

Even with it being an auction

How will you determine who gets what money going forward?

Last place gets $100?
2nd to last gets $90?

For this year.. What’s to stop everyone from using 100% on Trevor Lawrence? How will there be a tie breaker? If there is one, how are you determining the tie breaker?

It's a live auction, so theres no chance of a tie; the next bid will have to be above the last one placed. Someone is def able to spend all their money on Lawrence if they want as long as they have a dollar for each empty roster spot to fill out their team at the end of the auction.

Future years will have a base auction balance with a sliding scale based on final standings. Scale has not been fully determined as of yet but will be approx 400 base with a 20 alotment for each place in the final standings.

For the coming years there is also a salary cap which is charged against the teams auction dollars.

Honestly rookies need to be included in the rookie draft. Otherwise it's not really fair as someone can get a second 1st/2nd round startup pick in Lawrence just by bidding 100% right away. It doesn't really make sense to have a separate rookie draft unless you did the startup before the rookie draft. Even so every league I have been in, you draft a kicker as a placeholder for rookie draft pick (i.e. 1st kicker taken is 1.01 and so on and so forth)