I think there must have been a connection but I also think that Mollie must have been on the continent for some reason because she appears so suddenly. If she didn't want to 'help at home' after uni she would have jumped at the opportunity to teach at the CS. Incidentally when do we find out she is engaged?
As early as Princess
Though it's a good question as to who she got engaged to at that point - her husband in In Camp
is referred to as Alasdair MacDonald, in Goes to It
as a Mr Bennett, and in Reunion
as Kenneth Mackenzie, and in a short story in one of the Chalet Books for Girls (the second, I think, some 20 years after Princess
, so a flashback), her fiancé is Ralph Arden...