Came across a website deferally.com and they claim to be totally free.

Do a google search for "we buy houses [city] [state]"Sell my housewho buys housescash for my houselegitimate cash buyers, all with city state.99.9999999% of all websites out there are wholesalers.Then go to facebook and do a group search for "investors, cash buyers, wholesaler" then your city state.

I am interested in establishing a Short-Term Rental (STR) in Oceanside and noticed on the City website that STRs are permitted only in the Coastal area.

https://www.fincen.gov/resources/filing-informationI went onto the Fincen website and there are a bunch of forms...So I cant figure out which form to fill outWe have a few LLCs that hold rentals...

You can lookup the tax rate on the county assessor website - Make sure you are looking at or calculating the property tax WITHOUT any exemptions (since you’ll not get any as an investor). 

if the answer is no.. then please keep in mind this will be next to impossible for you go get unless your financially strong enough to walk in the local bank and borrow from them. no HML is going to loan that kind of money on new construction for someone with no track record.UNLESS you put in a huge amount of cash.. up front. so were We see all these folks getting scammed is they don't realize they really don't qualify for financing.. there is some notion running around that HML are just equity lenders they are not.. they are experience lenders IE how many have you done.. first time borrower VERY short leash. so you have the scammers saying no problem  the bigger the loan the bigger up front fee they hit you with and never fund.If you have the ability to go on American Greed website.. look up the episode on Remington financial.. they were the mother of the pump and dump Due diligence scams.. 

I tried the AM Best website but it appears a subscription is required...

I've reviewed the ADU rules on some of the different city's websites, now I realize how much variance there is just within the county...For example, Santee has a new owner occupancy requirement that will go into effect on any ADU's permitted after 2024 and a strict no STR policy, La Mesa on the other hand seems really ADU friendly.Does anyone here have recommendations on which cities in SD county to avoid and which to explore for ADU's?

I look up the seller's name on the appraiser's web site and then run it on the Clerk's web site to see how many transactions he has done before. 

What tool/website should I use to do a comprehensive background check?