I don’t get it. You’re in ‘serious shidduchim’ meaning you’re not yet engaged? – what are you doing then eating with your not-yet-fiance’s grandparents?
Talmud:- I will help you get it; You should read the letter in this week’s Yated Ne’eman Shidduch Forum, and I think that then, even you will get it.
If the young lady is trying to extricate a proposal from the young gentleman, inviting him to her grandparents, or/& asking them to invite him, is a wonderful way of indicating her desire for a proposal.
It is also a very strong observance of the 5th commandment, so a wonderful preparation for next week’s Parshah of Yisro.
As for you rebdoniel, just bring yourself in a french cuff shirt cleaned at a cleaner, and any gift is just fine.
But 1 more thing rebdoniel:- Please keep us posted of any & all developments after this weekend.