First question:
If your banana has just gotten its bunch, leave them on! They need to ripen and fill out before they are palatable. I am sure Pitangadiego here on this site has much more experience on that subject than me.

Second question:
Ensetes do die after flowering. I looked at your photos, and the plants looked big & great! If I were you I would chop it down and start a new plant. Afterall, they grow extremely fast, and in your climate you will have a good sized plant in no time. In any case, if it's starting to decline it's gonna look worse and worse.
Say, do you have any ensete-seeds you would like to sell? :-)

Erlend