Alright, since nobody else is going to take a whack at this... I need some information, like, what the intended effect is. ie: WHY would the exhaust and bathroom fans be wired to the furnace? If you can tell my why, I may be able to figure out how.

Also, by "3wire #14awg", do you mean actual 14/3 (black, white, red, plus bare ground), or are you counting the bare ground wire too (ie, black white ground)?

I wonder if those wires are for booster fans in the heat outlets, I can't see any other reason for them running to the furnace. Presumably they're fed in such a way so they'd run only when the blower was running.

Could they be wired so that the furnace shuts down when one of the fans is on? If the house was really, really tight, I suppose this might be desirable to prevent the furnace from back-drafting. But if the house is really that tight, there should be some other source of makeup air.

sorry was on vacation. anyway out here we have a code that specifies interlocking the primary fan with the blower fan in the furnace.
when the primary fan(located in hallway) is turned on, the blower fan(without heat)will also kick in. another rtm has 12/3 wired down instead of #14, a little oversized i'm sure but yes it is 3 wires-blk,white,red.