Just had a look, Andalucia is needed, so you are safe. No shocking twist at the end? I am disappoint!
Do you consider a WC to be a) Everyone dead or b) All provinces owned by you?
Seems to me you'll never stop colonialism from Europe... well unless you literally own the entire coast!
Are you not a fan of PU's, or just no opportunities yet? They're fantastic for BB-free conquest of Europe
Perhaps once you reach Golden Horde, the best course of action would be paying them tribute? This way they will be stronger, allowing them to take provinces from Bohemia and you won't have to fight them every 5 years, which would either make them weaker or require you to commit armies and attention needed elsewhere?