My source is a member of the cast. I was perplexed as well. I would have thought that all creature work would have been by the creature workshop as well. I asked twice about this, but was told again that the sea monster and the tentacle were "build by Lucas' people on the west coast". That seemed pretty specific.That's interesting information. Where did you find all that info? I guess it must have been the kind of anthology series with the same setting but different characters per show. It's hard to beleive that a Henson-produced production would employ another effects company to make animatronic characters (according to Muppet Wiki the creature shop justr supplied effects).
Any idea of the pilot was made but unsold before The Jim Henson Hour began, or if it was intended to be a regular series outside of The Jim Henson Hour, or if it would have been a regualr part of JHH (if the show had continued)?
In fact, when the sea monster arrived they were afraid it was too small and were going to return it to be rebuilt (at a large expense). Instead they pulled a prank and had it jump out at somebody sent on a pointless errand. It proved to be scary enough as it was.
I believe I was told that Lighthouse Island was filmed the year before the JHH with the intention of it being a pilot. I suspect that means separate, and possible even before the JHH was in production.
I can only tell you what I was told, I can't prove it though.