I see 1 property, a quadruplex, has a "current tax levy" of $7,639.98 and that the owner paid $1,289.89 in February of this year.

The wording in the above does not mention differences between annual levies and how that proration works.

My understanding is that with these methodology, the owner (or the seller) retains the title until specific conditions are met, so the seller gets to claim all deductions and expenses until the title is transferred.

There is a new 20% pass through deduction you may qualify for that could help you, but not everyone qualifies.

For tax purposes my understanding is an LLC doesn't give you any more deductions than if it's in your own name because you file on your return.  

If you use cash for personal purpose, it’s not deductible. 

If i am doing a house hack, by living in one room in a house and rent out the other rooms to tenants, can i still deduct deappreciation and repair cost from the house when i do my taxes?

They keep it and release it either upon your order or after the 7/14 days period setup in your account.You do have a point though, not for deposits, but for other type of refunds with your consent.What they should do is to copy Airbnb's way of doing, which is debit your account until the next payment and deduct it.

The purpose of the walk through is for you and the tenant to have an understanding as to existing defects you may later deduct for upon move-out.

Any fees should be calculated as a part of closing costs and are likely deducted from the check you’d receive.