I do not see anything wrong with them. When it comes to rivers, remember that they flow from high ground to low ground, and USUALLY do not split on the way there. they JOIN with others to make the larger rivers. Lakes might have many feeders, but only ONE exit flow. My one suggestion about your land shape, would be remove that land bridge at the northern tip of your largest lake. This would allow for some interesting sea lanes much akin to the Straits of Gibraltar. Anyhoot, follow those river pointers and you should be fine.