Regarding rivers you might find these useful: Essential River Guidelines for Mapping and How to get your rivers in the right place. Both tutorials are here on this site and are very helpful in getting the water flow concepts down right.

From what I can tell you want to have two exits from the lake on the East and that would be highly unlikely to happen except perhaps for a short time during a downpour. Maybe if men were involved in engineering something that would force this to happen but water will always follow the course of least resistance chasing gravity and if a lake has more than one exit at any time one of them always wins out and become the only one.

There are almost always exceptions but unless you have a solid reasonable explanation for it it'll never get past the "River Police"

Don't feel bad though because I think most of us learned a lot about rivers after we joined here.

edit:ManOfSteel types faster than me I guess