Narnia yes. If an ATR pilot wishes to now move back from VA to VARA to take up an F100 position they would have to interview and sim as they are not employed by VARA if they are on the ATR. The sticking point is that the ATR crew are under the VARA EBA still and that EBA has a clause in it stating that the company has to release a minimum of 10% to the VA jet fleet per rolling 12 months. There is also a clause about bypass pay which no one seems interested in pursuing.
As to your question regarding SO to 73 FO they have in the past held people for various reasons but essentially it is the normal route and there is no such cap applied.
SHVC not sure if I’m reading you right so apologies in advance, but you do realise the ATR is and has been for 2 years a VA operation right?