Filter results after searching
You've got your two obvious choices nailed down.  You're either offloading the filtering to MySQL (running 3 separate queries so that MySQL filters the data) or you're grabbing all of the data and filtering it on the Twig/PHP side.

Which one is more performant likely depends on 1) how much data you're talking about and 2) your environment (resources allocated to MySQL vs. PHP).

For your particular case, I'd enable devMode and analyze the performance metrics between the two methods while taking into account how fast the data might increase in the future and make an educated guess based on that information.