What vintage is this machine? It may have a different pump than the sleeve metered job on mine... but I've never found it easy to bleed when it's actually out of fuel. If you catch it and stop when it gets the staggers, you can clean the screen and it will restart without bleeding, but if it full out quits... it will take a while.
I'd say the black slime, etc is the result of water and probably algae in the tank. Dunno about the green.... unless it's dye in the fuel. Around here some suppliers like Ultramar dye their road fuel green.... and I mean GREEN like St. Patty's day beer.