An interesting strategy !
Honestly i'm not an expert on CSU as i've never chosen and used one.
But indeed the CSU maps here into Junior Suite City View.

But i see a teensy weensy snag.
A junior suite has 1 KING bed that sleeps 2 persons
An extra bed can fit 1 extra person
Makes 3 person occupancy at max.

As you are with 4 in total.
The sofa in the junior suite is not collapsable into a sofabed to accomodate the 4th person.

In my experience, IC AMS can only host officially max 3 persons occupancy for the following suite types.
In my experience as occupancy is maxed out at 3.
In our case as a family of 4, one must book 2 rooms as each room will accomodate 2 persons each = 4 total.
Hence my solution in advising to consider connecting rooms.