I am more inclined towards Dracaena or Cordyline.

I'd lean towards Dracaena, possibly Cordyline, but definitely not Pandanus. Didn't the seller have any ideas?

I was hoping it might be Pandanus, as I can't imagine Dracaenas or Cordylines surviving long term in mud.

Not a lot of mud here in NE Thailand, just very hot weather and the occasional torrential rain shower which occurred right before the photos were taken. Thanks for the input.

Is that a pic of the mother plant behind it? (2nd pic.) If you could get a nice pic of the entire mother plant, that would give us more information about the general form.

Have you considered Dracaena loureiri (cochinchinensis), the so-called Thai Dracaena or Thai Dragon Tree?