Does that mean he might be playable?

And Ermac is dead.

Ermac is dead because his ending in MKX is actually canon (Shang tsung has returned by killing him). Reptile, on the other hand, was just fine in the end of MKX. There is no reason for him to be absent from this game (just as for Smoke or Stryker).

I heard there are missions to find his secret or something?

Further more yeah Ermac is dead but got a new costume. Why hasn't Reptile? Why do you hate him NRS?

And still nothing about Smoke

They are referencing the movie a lot so it seems. I've seen in one of Max's Dood videos there is also that dining room from the movie (or sort of) where all the kombatants where with Shang Tsungs "And now for a tast of things to come". And also a dead Kano sitting in one of those tables (also referencing the movie where Kano and Goro have a conversation while eating).

If you look at the map in Goro's Lair on the left side, where the spot of Kollector is, is a way and there are the traps. And after the traps is the hidden entrance. The room itself didn't showed on the map.

Yes, there are so many references... It is the best krypt I ever saw. You can discver there a lot. And I think you meet Reptile again. But I don't know if he is playable then, if you find him again.

I'm betting now that he's loose you can probably check around the pit for Reptile. Makes the most sense for his next, or final, location. I wonder if you have to repair the bridge first?

So you can find him and smack him with the hammer ... That's it and you get a Scorpion skin... Boring