My custodian does not have a money market or similar sweep account to keep idle cash earning.

Also, if you’ve found certain markets more promising than others, what’s been driving your decisions?

There's no real hard and fast way or only 1 way or doing your first 2 points. your subject line suggests you're not looking to go to a large shop like a JLL or a CBRE which honestly I don't blame you those offices are usually pretty bloated.As far as monthly costs, if you are going to individually get a costar or other such license you are probably looking at $500-$1000 a month pretty easy in overhead once you have office dues, mls dues, marketing, etc. 

For your seller its an effective sales price of ask - 2% using your assumed $500,000 thats $490,000, a real good offer depending on your market.  

Considering recent market insights, reallocating your $300K brokerage account into a multifamily property while keeping your townhouse rented could be advantageous.Warren Buffett’s Berkshire Hathaway has accumulated a record amount of cash, suggesting a cautious stance due to potential market overvaluation.

I would recommend you focus on a couple neighborhoods that you would like to live in; and familiarize yourself with that market.  

Excited to hear more about your projects and experiences.What markets are you focusing on for your flips and buy-and-holds?

I’m active in the market and happy to share insights on neighborhoods, financing options, or connect you with resources.

Are you looking at investing in Birmingham or other markets?

(assuming market does not crash etc).