Also, the catalan is part of the queen's gambit family. I know of one line in the closed catalan that can transpose to the stonewall but apart from that they should not intersect.
It's just that bg2 is considered the main way of fighting the dutch as it makes it harder for black to attack the king, which is generally what he tries.
Na4 seems to be trapped by b3. I tried to make it it work for black but I couldn't. N6d7 might be better.
Qc2 and then taking with the pawn seems illogical, unless the idea was to keep the e4 advance which white didn't do. In the end black got the advantages of the nimzo without having to give up the bishop pair, and he also gets e5 in. And white didn't seem to get anything good from the d5 advance.
The four pawns against the alekhine is probably the most theoretically demanding of white's options. Just saying. Nf3 and the exchange variation gives white easier play.