At what stage of the transaction do title companies usually request identification from the sellers? 

@Jonn Vidal The limitation will be what your State/municipality allows for legal signatures and confirmation of identification, usually. 

This strategy hinges on the accurate identification of 'winners' in a volatile market and the successful navigation of the complex dynamics of post-pandemic real estate investment.

I plan to own my first rental property under a LLC in WA and I have my Unique Business Identification (UBI) but I am not sure if I need a separate business license to rent out my rental property?

Instead of getting an EIN, you'll need to get a TIN (taxpayer identification number) with the IRS (Form W-7) so you can do business in the US and be taxed accordingly.

However, a more important timeline is 45 day identification period.  

We just sold a SFR and are in the identification phase doing a 1031 exchange, so need to move quickly. 

ONE DAY before the 45 day identification deadline the seller advised they can’t sell the second property in the same calendar year because of capital gains on both.I scrambled and identified two additional properties before the 45 day deadline.

Verify identification by getting a copy of each applicant's driver's license and social security card too.Even if the property is located in a "C" neighborhood, good tenants are possible to find if the place shows well, repairs are done and it is priced right. 

It might be worth getting (2) forms of identification from prospective tenants to prove identity.