As I have written, we have two conflicting opinions on the matter. It is your lawyers vs. Fantastic Four's ones. Meanwhile company is preparing to make you and four of your fellow captains redundant. They know that they can do it with impunity, as it will take ages for your court case to reach the verdict - which might not necessarily be in your favour.
Ab33t has pretty much answered your question about practice in the most of the companies; if one fleet is downsizing, there are not enough volunteers for type switching, for lowest ranking on the seniority list it is either moving to other type or to other company.
The company cannot make promises on whether they'll ever return you to coveted A320 RH seat as the MGT is absolutely clueless about the company's short term future, let alone what we'll do next year. Airbus deliveries have been deferred by two years. No matter how the MGT is trying to present it, Julka will be parked for next season and I'm only hoping that the rest of the fleet doesn't get parked alongside her. Who knows, if it really gets bad, maybe your severance package will exceed my remuneration I'll get from the company till the day we go under.
For F/Os we have a punishment being stopped from the upgrade till the whole group having criteria at the time, rotates for the left seat.
A concept that is very difficult for people living in the normal world to understand. At CTN, when the upgrade is offered, one can't realistically deffer it as it might set one back for a couple of years, with all the financial consequences.
Good luck to you... and to all of us... we'll need it badly.