Kikapu – hello.
I live in the South. I empathise with Viewpoint's viewpoint.
His concern: maintaining TC control of the 5 seats.
You state the the two states must allow for freedom of movement between all ethnicities, under EU law. You state that dropping the TC land to, say 18%, will ensure a homogenous ethnic state and a guarantee of 5 seats.
This two statements are oxymoronic, as you're only looking at how the states will initially look immediately after an agreement. If GCs subsequently move into the TC state (as they are perfectly entitled to and more than economically capable of) they will gain an increase in political power, negating the TC protection of the 5 seats as the state will no longer be homogenous. So the plan does not offer the long-term protection along ethnic divisions that Viewpoint seeks.
Any statements 'regarding this is not likely to happen' are irrelevant – we are looking for political guarantees not sociological predictions.
If we are to play prediction games, one could in fact argue that, with TCs potentially moving south and the disparity of wealth allowing GCs to cheaply purchase TC property, many could easily afford second homes encouraging an osmosis of the poplulation, as TCs use this money to buy elsewhere. This is pure speculation – the colder argument is found above.