I doubt MYT will pull out. They have always had a big base at Cardiff until recent years, and have this year upgraded to a A321 - considering they only have 4, that cant be bad.
Unless another airline is looking into CWL which both MYT(Airtours etc) and Thomas cook can use, they will lose alot of business. (Maybe XL are coming back??
)
No major decisions have been released about the future of TCX/MYT as yet, but i personally think it will be CWL that will get a winter base
As for baby, whilst this may tie in with the mainline fleet, can they really afford to change? Especially as they are still taking on more 733's.
Could be a longer term option tho, who knows!