I don't see a massive need for it to be mentioned at all. Even if Fulcrum herself shows up (certainly not impossible, but doubtful for logistical reasons), it's not a given that the topic will be addressed. Season one has been tight as a drum. Not a line wasted, nor shot squandered. I can't imagine season two will be any different in that regard.
For me, the dilemma for Mon seems to be that whatever her daughter thinks she's willing to do right now, she's far too young to truly understand what she's getting into. Mon seems to have had a very orthodox Chandrilan upbringing and was similarly betrothed at a young age, only to become more enlightened/jaded about the whole thing later in life. So by allowing this to happen, she's potentially sacrificing her daughter's future happiness. That she's up for it is just a sick twist of the knife.
As for where this will go . . . well we know Mon will end up fleeing Coruscant mid-way through the next season (that's just math), so that's three or four episodes and at least two year long time-jumps for things to play out.
Honestly it could go either way. Children if high profile citizens disavowing, denouncing, and even reporting their own parents as enemies of the state is far from unheard of in fascistic totalitarian dictatorships. Indeed Leida may be the one to expose Mon and cause her to make her treasonous speech to the senate and flee the capital.
If so then the ISB and especially COMPNOR are going to want Leida kept very safe and able to give public statements and propaganda about how mentally unstable and deviant her mother has always been.
On the other hand the next few years could expose Leida to the very ugly truth about the Empire and what unquestioning submission to tradition and authority can bring. She may even end up running missions with Leia and Holdo.
She
literally introduced him to Jyn in 'Rogue One'. That they will meet is already a foregone conclusion.
