a little under pitched but not much. DON'T MOVE IT TO SECONDARY. if you have under pitched and stressed out the yeast you don't want to them remove most of them from the beer. Let them stay to clean up after themselves as much as possible.
Take a gravity reading. it's the only way to know what is going on in there.
I would not try to dilute anything at this point. Let it work. you've just got a somewhat stronger beer than you intended. Blend at serving time with a smaller beer or sparkly water if you must.
I don't know what you mean by two layers of floatys. but I don't think anything is wrong.
+1 and diluting at this point would just oxidize the beer.
Not exactly true. If you just add water you will add O2.
Here is a way to do it. Boil the water, transfer to a purged keg, purge the head space if you don't do closed transfers, allow to cool, the add to the beer.