The first coach of each 4 coach set and either the first and 5 or last of a fixed 8 piece will have a toilet.

We cannot show the mock up drawings we have seen in public due copyright, but accessibility regs require the wheelchair space to be in the same coach as the wheelchair toilet and thats what the mock up shows

The trains will always be the same way around (at least until DART underground is built)

Intercity trains are currently undergoing a refurb where the wheelchair accessible coach now gets different coloured external doors

Has there been any suggestion of open gangways between coaches? I came across them in Helsinki, and they make for a fair bit of extra space when the train is busy, as well as making coaches feel a little less isolated when it's quiet.

The mock up in the members area of the forum has the drawings

So it does. :-)

No chance of any consultation on the designs?

We have asked before, no word yet.