Would it be prohibited for me to purchase the replacement property and then deed it over to a new LLC after I purchase?

for "regular" residential investments, the maintaining the limited liability aspects can actually confound and/or make it prohibitively expensive for a single investor to do. 

Prohibited Transactions: While the IRS does not dictate investment assets, it does have rules regarding whom an IRA may have transactions with.

I expressly prohibit paying guests.

You should get one that specializes in SEC law and have them prepare a PPM for you.Reg D 506c exemptions from registering for a security only allow you to take accredited investors.Reg D 506b exemptions allow you to take sophisticated, non-accredited investors, but you are prohibited from advertising, which can mean a lot of things. 

In case you are eligible for the Solo 401k, here are some of the benefits it would offer compared to a self-directed IRA:Solo 401k contributions limits are roughly ten times higher than IRA limitsThere is no custodial requirement for the 401kYou don't need the additional expense and administration of an LLC to have checkbook controlThere is a built in-Roth component whereas IRAs are either traditional or Roth, not bothA spouse can also participate in the same Solo 401k planThe Solo 401k has additional tax benefits over an IRA when investing into real estate using leverageThe penalties for prohibited transactions are less severe, though it's best not to utilize this benefit :)

I would imagine your HOA prohibits it.

As soon as you possibly can, I would amend your lease to prohibit operating a business out of your property. 

Let your agent know that you now rent the place and ask if your home owner's policy needs updating.You can prohibit pets, they chew things, bend window blinds, disturb the neighbors and make wet spots if left unattended.

That Oregon prohibition would be pretty unusual.