And even those aren't really passive because you have to be consistently monitoring the performance of the vehicle to be sure they're not running it into the ground, participating in capital call discussions, etc.

1) Will you lose material participation in the cost segregation if your property is in a neighboring state?

bare bones website  no mention of he staff or principals.. so maybe.. just dont send up front money .if they hound you for up front money then you have your answer

It would help if you could participate with someone else while gaining knowledge, what I mean is, its better to be applying or thinking about applying the knowledge as you learn it rather than just absorb a bunch of knowledge but not go through the difficult part of applying it to the real world.One thing you can do is look at strategies you would like to do.

There's barely any inventory for a reason.

@Michael Plaks has a great post on this topic.2 - Assess the value of those tax deductions to you: The value of a deduction depends on (a) whether you're actually able to use it to reduce taxable income and (b) your marginal tax rate.As an STR, assuming the average rental period is 7 days or less, key items to consider are: (a) material participation and (b) avoidance of "excessive" personal use.

I only have 9 units and see some require 500+ units to participate. 

Quite the opposite: I invest my own personal money in each deal alongside our members, as just one more participant.

No promises but what you may find yourself in a deal  with limited $ because you learned what your network is looking for or someone in your network allowed you to participate in a deal.  

@Don KonipolWe have done very similar on a quasi participation agreement where it’s a 12% loan and 2 points at $500k.