I asked around a bit about my kiddush question. A big T’C I consulted with told me “we don’t do it”. I told him I’m looking for a real reason, not “what we do”, if I start doing it it’ll be become what we do in my fam and problem solved.
Anyway, he said a svara that if he’s not up for kiddush of night he’s not נשתייך to it in הלכות חינוך or something like that. I responded that he’s up after plag which technically is a zman which is ראוי לקידוש. He answered that if that’s the case he should be making his own kiddush by plag! I may start doing that.
"What we do" *is* a real reason.
That case I mentioned above who makes havdalah until Tuesday for people and Friday night kiddush by day? Well, it does cause mocking and leitzanus from kids and people who are becoming more observant. When there is a shiur on a Monday night that starts with Havdalah, people laugh and you run the risk of turning havdalah into a joke, and/or the person doing it becomes the but of the joke.
When your kid goes to another house and hears regular day-time kiddush and not the Friday night kiddush he is accustomed to, you can't be sure how that will affect him. Is he going to brush it off, or is he going to feel awkward that he is "different" and start thinking of you as someone with OCD tendencies?
My son used to make kiddush before going to bed Friday night. We made like a mini shabbos seudah.