kumravadi,
best wishes to your daughter's engagement, and subequent marriage. .
i have not heard slokas recited in nichyathartham ceremonies before. but that does not mean, that i have seen everything or it is a wrong practice. it is all in our minds, and i feel, that you are under the impression, that a dash of religiosity, in what is purely a celebratory function, will do good to the senses. and values.
the only people whom you have to clear, i think, prior to doing anything, is your potential sambandhi. they might or might not like it. it does not hurt to ask them first.
and if your future sil is into these things, it might not be a bad idea to consult him too.
when it comes to marriages, tradition et al, it is never good to break traditions or spring surprises.
that has been my experience.
God Bless the young couple.
