This looks like a great trip!
No, the map is totally incomplete. Pretty much all European trains are included.
You get 30% discount on the ferry to the Netherlands (although the discount must be renewed soon).
Travel within cities is not included but tickets are rather cheap. Suburban trains are included in Germany but not in Paris for example (RER network). Again, not worth using a pass day for those.
The direct route from Paris to Milan is closed for quite some time due to a landslide. The most logical route is via Switzerland. If you wish to travel on a splendid Alpine railway have a look the Bernina route (takes longer ofc).
Also possible via Nice and the Mediterranean.
The Simplon route will be closed from June to September meaning rail replacement buses. Better to travel via Gotthard or Centovalli (have a look at Google Maps).
Reservations are mandatory on fast/high-speed trains in France, Italy + some cross-border routes. Have a look at https://www.seat61.com/interrail-and-eurail-reservations.htm
Questions welcome.
Btw @Camilo. @Mukhammad the Eurail map is confusing so many travellers (thinking they're tied to a few mainlines) that I'm not sure it's worth keeping it...