California for example taxes, HOA's, Sale prices all seem to eat any cash flow right out of the gate.

Just like your saved after- tax money in your bank is not taxed each year. 

Unless you tell your friend to work 100 hours and you work 101 ;) According to prior tax court cases, travel time does NOT count toward material participation time.

@John FongCalifornia is generally more cumbersome than other states when it comes to taxes and filings.

I am curious what tax benefits I can claim, if any, specifically:1. 

actual insurance, actual taxes, actual utilities, actual capex. 

I got a house and have been house-hacking with Air BnB, now is the time that I'm looking for doing the taxes with my W-2 and the Air BnB income, does anyone have any recommendations on an accountant in the upstate South Carolina area that is familiar with doing taxes for real estate investments (ideally specifically short term rental). 

@Jane Mipsey putting the investment property in an LLC is purely for limiting your personal liability, not for tax purposes.

4) Applicants over 18 - what about full-time college students still being declared as dependents on parents' tax returns?

Not sure if I should say it's not my problem and he is now delinquent so he owes the late fee as well as the rent that needs to be paid immediately?