I'm frankly surprised about your quick germination for the Big Guy's. Peppers take a while to germinate, even with heat. Good idea to dig in and check and, yes, kind of surprising that they even haven't started to break open. You're sure about the soil temperatures, and that the two types of pepper were treated similarly? What does the "top of the media" temperature mean? How was that measured? The top of the media will be cooler than the soil temperature because it is exposed to the air.

I planted 1/4" deep, and stuck a digital meat thermometer 1/4" in.

If you wish to check viability (and it's a decent method for starting a few seeds anyway,) germinate them in paper towels. You can find a quick tutorial just about anywhere. Paper towels just need to stay moist and warm. If any germinate, plant them in a good medium and your all set.

That's a reasonable way to get soil temp, and I agree with rgreen. Just germinate in a moist paper towel and, when the seeds first crack open, plunk them in potting mix. That way, if the germination rate is poor, you select out ones that are good.

I know they don't need the lights yet, but I have other things (tomatoes) already growing and green in the same area that do.

Instead of the paper towel, try germinating in a damp coffee filter. Once the sprout appears it's easier to detach from the coffee filter, the sprout tends to grab onto/grow into the paper towel.

I don't use heat mats, but sometimes the peppers seeds have taken up to a month to germinate (usually with hot peppers).

Ok...today one broke the surface.

Because of difference in types of peppers they can germinate anywhere from 3 days to 3 weeks, hot peppers usually take longer, Be patient :)

I had some take 3+ weeks this year. It cant take a while with older seed and cool soil temps.