Read twice, order once

Months ago I ordered a cover/grille assembly for the light/fan/heater unit in my bathroom - the original had been lost prior to me moving in. I also got the unit's install guide emailed from the manufacturer. I scanned the wiring diagrams only long enough to confirm that I'd be able to wire everything on my own, but failed to note a key point - the switch for this type of unit is more specialized than the standard 3 switch combo I then went and bought at Home Depot. So, now, as I'm finally ready to finish wiring things up, I realize I can't. I just put the order in to the manufacturer for the specific switch assembly I need, but meanwhile I'm feeling a little dumb, and a little irritated that I can't get this done as planned. Planned being a relative term of course since I'm only getting to it now.

I did at least complete the wiring from the service panel to the unit. Originally I was going to swipe an existing run that goes to an unused heater in the bathroom:

...but it was clamped into the heater unit before the room was finished off, and thus would be a bit of a pain to undo:
Instead, I reasoned that, since I wouldn't be using that heater unit, I could branch the line for the overhead unit from the same run and not have to worry about overloading the circuit:

exhibit A: the box

exhibit B: the box open, showing the line coming from
the service panel and the line going to the old heater.

exhibit don't-be-an-idiot: even if you know you flipped the breaker,
check that the line isn't hot before sticking your hand in there.

new branch tied in to all three wires

...and coming up to meet the wires running from the overhead unit.

I took too many pictures of semi pointless things here, so you'll have to take my word that I attached these two wires to each other and am now just breathlessly awaiting the delivery of the switch assembly. Maybe you'll get some more pictures of that. If you're good.

Update:
Pics of the wrong and the right switch (specialty switch needed for the job is on the right in both pics):