Well, I've built push-pull 2A3 amps and push-pull 6B4G amps. The 2A3 amps were AC heated with one hum pot per tube, and I couldn't ever quite get them quiet enough, but I was messing with this a long time ago.
(The hum pots were on the bottom) This was 15+ years ago though, so maybe I could overcome that today.
Within the last couple of years, I redid some Heathkit monoblocks to use 6B4Gs (6.3V heated 2A3 in an octal base). By all accounts, the higher filament voltage should've made them quite a bit noisier, but I used one hum pot on both tubes and everything was OK.
If you wanted to be really safe, plan for DC heating of the 2A3s. This means separate windings, mostly because AC current is just so high in general. You can use a 6.3V CT transformer at about 4A to DC heat one 2A3 with a full wave rectifier, a small resistor, and a beefy 10,000uF cap. The small resistor value will be 0.07-0.1 ohms or so depending on the transformer winding and the ESR of the filter cap. If you want to heat both 2A3s off the same winding, then you'd need a 7+ amp winding and two of those power supplies. I can look up the diodes that I use if you want that don't require a heatsink. Most will.
With two separate DC filament supplies, then where our output tubes are sitting, tie the negative filament side of each supply to one end of your 10 ohm hum pot with a 22 ohm resistor, then do the same with the positive end. This will mean four 22 ohm resistors (1/2W is fine for a 2.5V filament) will be required to connect up the filaments to the single hum pot. The presence of the extra resistors will allow each supply to be a bit more independent compared to just paralleling them and crossing your fingers.