The Khorns and Lascalas sound a lot alike at the top and middle ends. The only real difference is the lows, the Khorns have more bass extension. They go below 30 hz with no problem whereas the Lascalas fall off at around 40 hz. Aside from that, they sound the same, not surprising since they are using the same tweeter and midrange drivers. By the way, they do not sound nasal or boxy or honky, at least the setups I heard didn't at all. The sound was sharp, free, effortless, and enveloping.
The Cornwalls sound different, the highs were good but not as good as Lascalas or Khorns. Same thing with the Heresys, but more so.
If you are looking for a retro look, any of these will do, if you want a retro sound, I would go for the Cornwalls or Heresys, as the Lascalas and Khorns sound terrific, even by todays standards, they do not sound dated at all, even though they are older models.