Unless you own the house cash, in addition to the advice you've received, you can't just transfer a house from personal to an LLC without risking the option of the loan being called since the LLC does not have two years of tax returns.For new investors without cash to buy, LLCs are about the biggest cause of analysis paralysis out there.

However, since we don't have any experience in rentals, we don't know if we should buy a single home and get it rented out or buy a multiplex.

Do not buy real estate if you have bad debts.

I've done my analysis and found a deal that I really like, that has seller financing that balloons in approx 2 years.....cash flow is pretty attractive, but the down payment is around $300k, and I was looking to put d...

I have 3 ( 1 condo +2 townhome) rental and one primary home (single family ) all in San Diego and for my rental portfolio of buying with my own money i am done.

If the intent is to flip it, there are two ways people buy houses 1. with borrowed money 2. with their own cash.

So if I were in your shoes I would want to be really confident in the exit strategy. 1) confirm rent estimates 2) confirm ARV and the demand in that area to buy a house like that in the price range 3) are there banks willing to refinance at the LTV you want with the seasoning period you have. 40k for a house of that size that needs that work would be the cost of materials alone where we live in WI, so verify your estimates.

I want to buy a 300k property and i have over 300k cash and a company with 7 figures revenue, but cant get a loan anywhere near FHA rates. 

As an investor, your primary goal is probably to buy at the lowest price (you make your money when you buy at below market value), fix it up, and either hold or sell/flip.The seller might realize they "don't know what they don't know"....in general, investors sometimes come across as "transactional" (they ran the numbers, and just want a yes or no from the seller). 

Quote from @Kendall Jackson: I’m trying to get started in real estate to provide additional income for flight school and eventually buy a home in San Diego.