I don't see where the yellow and green wires come into the furnace from the tstat.
It's almost like they splice the wire somewhere and the wire colors changed between the tstat and the furnace.
On the tstat I see white, yellow, green, red, and blue (with the blue not being used).
On the furnace I see white, black, red and blue.
A volt/ohm meter sure would be nice to have right now but, i think I know what's going on and can advise once you confirm what happened to the yellow & green wires.