@VictoryFirst
Tank Armies cannot amphib attack as an Army. They would lose there bonus. They can reform after battle, if there are enough to do so.
If I remember correctly, 1 of the 2 Armies/Corps, must be the active one. If you are in your Capital, you can have both Armies/Corps active.
The other Armies/Corps can be part of the 10 required land units.
For individual Armies/Corps, only 1 can be a Oberst, PG or Commiesar. So can’t have 2 TG and 4 Tanks make up a Tank Army.
Edit
So in your example, only one of the Waffen Armies would get the bonus.
However, You could have 1 waffen and 1 PG be the Armies and the other two make up the 10 land units.