Teleport and Detect Thoughts

Tomb of Annihilation Spoilers ahead!

My group is 13th level and after mucking around the jungle they are finally beginning to realize they can just teleport to Omu. They have Salida with them. She knows they are there because of the Death Plague. She has told Ras Nsi about this and he is intrigued to meet them but now that Salida has seen the PCs power (and how the Paladin deals with evil) I'm thinking he would be cautious.

So two questions:

First, a rules question...how would you handle using Detect Thoughts on someone very familiar with your destination to get a better fix for your Teleport spell? The party Wizard player wants to use Detect Thoughts on Salida to use her familiarity with Omu to improve his chances of accurately teleporting there. Would you allow this? The wizard is being very cautious...he wants to be at least "Very Familiar" with his destination. Right now, having spoken to Salida about the location of Omu, he is only at the "Description" level. Personally, I'd rather jump to that portion of the adventure...13th level PCs traipsing about the jungle isn't all that interesting. So I'm inclined to allow it...just this once at least.

Two: Salida wants to get them to Omu because Ras Nsi told her to bring them to him...but I'm thinking at this point Ras Nsi will want some insurance against an obviously very powerful party from just teleporting right into his home...but he is also getting concerned about the Death Plague and wants to solve it (and will want the Soulmonger to turn the Yuan-ti Anathema I gave him into his god...I'm going to give it some lair actions and legendary actions to make it more fun...for me).

So...where would you have them teleport? I'm thinking Salida will let the Wizard read her thoughts to get the location. She will think very hard about where she wants them to teleport to and no save will be required. But if the wizard tries to delve further she will get a save to stop him...if she succeeds the spell ends. If she fails he could learn two things: 1) she's using a sending stone to communicate with Ras Nsi and 2) if she is sending them into a trap, it will reveal that.

Or maybe Ras Nsi will rethink allowing them to come into his lair at all (the Paladin with his Sun Blade will concern him the most)...maybe he will direct her to send them somewhere much more dangerous...where?

For the rules part of the question, I don't think detect thoughts would get any better than a description. Teleporting is supposed to be a bit risky. If I didn't want to deal with a mishap, I'd probably just fudge the roll. Or decide that Salida has an object from Omu.

Could still use detect thoughts if they are suspicious of a trap, of course.

I would not let Detect Thoughts result in anything better than "Seen Casually"; if Salida is indeed concentrating to 'help' the wizard see the location, then I'd say at least "Viewed Once", and probably "Seen Casually". As [MENTION=60210]jaelis[/MENTION] noted, Salida having an object from Omu could avoid the question entirely, although it would be nice to allow the wizard to feel clever for thinking of using Detect Thoughts.

I like the decision you're already leaning towards. It sounds good, and interesting. The bit about using the detect thoughts opportunity to learn more is inspired, too.

Though I'd make her save with disadvantage because she's already let the wizard in partway. I would do this in part so that in the future the players looking to read some other target's mind may try softening them up first to get at the disadvantage.