I believe it's a $100 application fee.https://sos.nh.gov/corporation-ucc-securities/corporation/forms-and-fees/domestic-and-foreign-limited-liability-company/domestic-forms/

I don’t know if I should try to secure a HELOC as soon as possible or wait until I’ve been able to save up more of a cushion in cash.

You can ultimately be successful anywhere on that spectrum, but some approaches increase your chances of success, and others increase your chances of arriving at the bottom of the mountain in a ski-patrol toboggan.

But they didn't report anything about the door damage at that time and also never mentioned about it before this pre-move out walk through.In this case, do you think I can deduct the cost to fix this damage from their security deposit?

So you should remember that reasonable wear and tear is NOT damages and may not be offset by the security deposit.

Instead, make sure to prioritize the security deposit and use discretion in choosing renters.

Of course, set your rent and security deposit figuring this. 

I will have a separate bank account for the LLC, and I have separate accounts for the rent, security deposits and cash to pay for expenses for the property.

I was reading that Fanny Mae and Freddy Mac have specific requirements for refi when it comes to condos, and one of them is that it can't be an investment security, which the site said was an investment condo. 

Different areas have different rules but I keep it quick, brief, and electronic, no one knows why they were denied but everyone knows up front there will be many applicants and I pick the best, security deposits are non refundable.