Dual wielder and polearm master feat combo, do I have it right?

Question

The dual wielder feat allows me to use one-handed weapons for two-weapon fighting. The polearm master allows me to use my reaction when someone enters my reach.

If I would be fighting with a longsword on one Hand and a quarterstaff in the other I'd have all of the following options for attacks:

• Longsword attack action, quarterstaff bonus action
• Quarterstaff attack action, longsword bonus action
• Quarterstaff attack action, quarterstaff bonus action with 1d4 as damage die

And I would get to use my reaction to attack with the quarterstaff when someone enters my reach.

Is all that correct?

I ask this question to better understand how the fighting styles and the feats in D&D 5e work. I am quite sure that it would be sub-par to really combine those two feats.

Answer 1

Yes, that's correct. Dual Wielder allows you to use non-light one-handed weapons for two-weapon fighting, which both longswords and quarterstaves are. And Polearm Master works as long as you use only one of the listed weapons for your Attack action.

Note that this means that if you have Extra Attack, you can't go longsword, quarterstaff, quarterstaff bonus action - you have to keep it purely quarterstaff attacks.

And, as you say, you can take an opportunity attack when enemies enter your reach. Interestingly enough, you don't have to take that attack with your quarterstaff! I was surprised, but here's what it says:

While you are wielding a glaive, halberd, pike, or quarterstaff, other creatures provoke an opportunity attack from you when they enter the reach you have with that weapon.

Errata changed it from "when they enter your reach" to "when they enter the reach you have with that weapon", but your reach with your quarterstaff and your longsword is the same, so technically, you can take that attack with your longsword if you want!