Spring, Day-time wedding
I would think Ivory white would be great, after the wedding you got a pair of trouser for your weekend and a beater linen jacket?
In fact, why does it need to be in suits? how about a navy jacket with bright trouser?
Hopefully the bride is actually well dressed........
That said, most people in the real world would probably just think you look nice and not notice, especially if the pinstripes are subtle as you say. So if that's the outfit you want to wear, then go for it.
Make your trousers a part of a medium grey solid tropical worsted wool suit and you will perfectly attired with the balance of your choices.
You could even change your shirt to a white one, if you desire to bump up the contrast. You could also wear a very subtle medium grey Glen or self plaid suit for something a bit sportier.
The nice thing is that with your choosing such a neutral pallet for your outfit, you can wear nearly any color of socks and dress shoes that strikes your fancy. Medium grey suiting is perfect for weekend and resort wear at any time of day or night, except the most formal affair.
I prefer the appealing sophistication of medium grey suiting to that in beige or tan for the all above occasions if not because beige and tan are best limited to daytime wear, then because they can appear rather unsophisticated in all but the finest of fabrics.
No doubt, you'll change into khakis or chinos with some sort of sport shirt like a button-down collar or polo and sensible shoes before hitting the park.
Man you just reminded me about regretting not buying a Mickey Mouse tie when I was in Japan! And it was surprisingly tasteful. It's a woven repeating pattern tie of the Mickey Mouse silhouette formed by negative space. First glance the tie just seem to have a unique pattern until further inspection reveals Mickey and the mind is blown!
I am not wild about the above-the-waist, though. Aside from the knot's dwarfing the tiny collar points, nothing looks off. But the whole thing seems a bit studied. Might be because the scales of the herringbone, shirt check, and tie pattern are very similar.
Anyway, it's miles better than all but a small minority these days.