As for 'everything must be done through the LLC' - your property insurance must be covering the LLC (not you personally), your bank accounts that you receive rent and pay bills out of must be in the name of the LLC, your utilities must all be in the LLC name and not your own, etc.

Getting in early (like before February 15th for personals  and in January for business returns) seems to be the secret the best I can tell.You get an automatic 4 month extension - but if you did not pay all the taxes owed (within 10% of what you owed by the filing deadline) you  will incur a penalty for that… and if they aren’t filed by the extension date that would be another one as well. 

I would rent the extra room(s) similarly to a medium term rental property.

The last deal I closed up in Aiken Sc the attorney balked and would not pay the wholesaler.. this led my agent to do a work around and we got it done..

However, this isn't to scare you away, because I was house hacking my expenses dropped substantially and I was able to pay that 20k back pretty quickly.

Hopefully this is not some news to you, but sellers are no longer having to pay buyer agent commissions, now is a Choice, which might be confusing, but there is nothing to worry about. still, it doesn't change the fact that to maximize profit, it's wise for sellers to offer a buyer agent commission, attracting more qualified buyers to the listing. and for buyers, the main change is the need for a few extra forms and agreements before viewing properties. 

You may need to have survey performed on the property that might be paid for by you or by the seller or it may be common practice in the area for particular pardon you to pay for it.

This can help pay for the mortgage.

If the double needs updating and you are handy, you can force appreciate the unit you are living in while paying no or almost no money for the home as your renter covers most of your expenses.By the time you are done renovating + 3-5 years give or take you have a forced appreciated property. 

Think about if the income from your rental went away temporarily… tenant quits paying rent and you have to evict them, or whatever.