My ideas for games.

Hi Boxoftricks,

It sounds like your approach to game development is similar to mine - lots of notebooks that get filled up when inspiration strikes! Hopefully, some discussion about the first game will help move it forward...

In the early 80's there was a game called Scotland Yard that featured detectives chasing Mr. X around London (I believe this game is still in print). Instead of two boards, this game used a single board that always showed the locations of the detectives, however Mr. X only placed his token on the board every 5th turn or so. All the detectives had to go on was a chart that showed how Mr. X was moving around London (taxi, bus, underground, etc.). You might be able to use a similar approach to handle the invisible ghost on the same board as the busters. For example, the busters might have some way to scan for the presence of the ghost; if they scan for the type of trail the ghost left behind they will get a clue as to the location of the ghost. Perhaps something simple like moving down a hallway leaves a cold temperature whereas moving through a wall leaves ectoplasm.

I imagine the busters will be wandering around the house searching for the ghost initially with a sudden rush to surround or trap the ghost before time runs out...

You have lots of exciting ideas here - good luck with your development!

I like your ghost Idea, and Robo Rally's movement system came to mind.
In Robo Rally, you place your moves face down so nobody else can see them. Then you flip the moves over as the turn progresses.
This idea could be used to simulate the ghosts movement. The Ghosts can have their moves placed face down while their location from last turn remains on the board (or even a trail of where they've been). Their face down movement card represents where they just moved, but players won't be able to see where that is until its flipped face up.
This could even allow for a co-op game if you wanted instead of just ghosts vs. busters.
Movement cards could simply be directional+number of spaces, or could be made more complex.

As for the Moon Idea. I like the thought of two elliptical paths. Each location along a moon's path might have a number or color value and each moon's values are compared/added/what have you to produce a certain in-game effect. Perhaps it becomes some sort of building/resource management game, but watch out for when the moons cross because they'll flood the land.
You'd have to weigh your options and plan a strategy based on the moons current and future movement.
It could even be a card-based game where some cards change what they actually do based on the alignments.

I like these a lot.

I'm intrigued by your "ghost" concept, and I wonder whether you've considered that the ghosts and the busters might be challenged to work cooperatively toward a common goal, e.g. preventing some horrific disaster or locating some enchanted family heirloom, either as a game goal/rubric, or as an intermediate play element.

The idea of the ghosts (and their play action) being unseen by the busters, except under special conditions, is problematic as far as the play mechanics are concerned. Role-playing games resolve this issue by having an omniscient dungeon master who supervises play, but I gather this is not the direction you see the game going. I think the "hidden cards/tiles" which are subsequently revealed is heading in a practical direction; have you actually tested how this might work?

The Ghosts mechanic could work in a similar way to Scotland Yard, where the Ghost player would be forced to make their location known periodically, at specified intervals through the gameplay. Scotland Yard does offer other clues, however, in the form of Taxi, Subway, and Bus tokens, showing the detectives which mode of transport was used by Mister X. For your Ghost Busters to have a sporting chance of deducing the location of the ghosts, a similar hint system should be put into place.