Yeah, but Wookie... Look at your lists. You clearly have all the ships you need to build identical fleets, but also to vary it up. I am sure you've flown a lot of different fleets. But this post is advice for a new player, not advice for a guy who has the ability to field both huge fleets of identical ships AND huge, varied fleets. The post is about what a totally new player should buy, and for a new player I think the idea of spending hard earned money on a totally identical fleet is just minimizing the variety of the game unnecessarily.
Once he has a little variety and has experimented with some ships to figure out what types he enjoys flying, and once he has some more money, sure, he can pick up fleets of four of the same ship. But I absolute don't think that a TIE or X Wing expansion should be his first non-core purchase. I don't even think it should be his second non-core purchase.
Again, I'm not taking issue with that, I'm taking issue with you lumping in some opinionated statements on how uninteresting you find single-ship builds. If you want to encourage him to try out some different stuff, pick up some other ships he can't find in the core set (although both the X-Wing and TIE sets come with very important pilots for those ships, as well as upgrades not in the core set), that's great - but you're packaging in some pretty personally opinionated sermonizing on how a rainbow squad of ships is better, and I take some issue with that.
I would go so far as to argue that for a new player, trying to learn to fly four or five completely different ships at once and figure out how to use them is actually much more intimidating and much less helpful than giving him a basic 3X squad of Wedge, Biggs, and Luke or whatever and having him go to town. Trying to learn to master the X-Wing, Y-Wing, A-Wing, B-Wing dial all at once, and then learn to fly something like the Falcon well (which is a whole other skill set that takes time to develop) can be overwhelming for a new player.