Adding new aircraft at this early stage seems feels premature. The additional complexity and operational cost would seem at odds with operating a streamlined model. Be great to see the A220 join, but that would mean 4 types; 175, 220, Q400's and ATR.
I'd have thought consolidate what you have, rationalise the marginal routes and align the operation to Virgin's hubs as stated, then when profitability is achieved then look at the fleet equation?