I had a few emails, but not sure what's a good price.
Since you know next to nothing about them and chose to buy them at an auction, that was probably a "good" price. It was at the very least the current market value when and where you bought them.

The largest value w/fastest turnover is definitely in the crossover pair which you can expect an ebay price of 125 - 150 this time of year.

421's are a "dime a dozen" and of little interest to the hifi enthusiasts that frequent this site. Last pair i sold were 421-8LF's in excellent cosmetic and working condition for 100 bucks. I usually don't bother with 421's unless they're essentially free. I agree with OG about selling 421's singly as the educated market for them are usually looking to use them in instrument amps/cabs(guitar, bass, keys). Most other Altec products get better prices as pairs.

Too bad the 1225 horn cabinets weren't included with the 1215's, those would have been worth several hundred.

The 1215 cabinets might generate slight interest, but shipping will be cost prohibitive so you're limited to a fairly local market. For those with the abilities and facilities, most Altec cabinets can be built new for the cost of shipping or less.

The 816's might get a bit more interest as they're somewhat more easily handled and they have the classic Altec horn flares that many will recognize.

It's been my experience that i enjoy much happier endings when i do my research before i buy, rather than the other way around.