SO many Questions!
I'll try:

Since it will be a Holiday weekend, I'd go with Amex for Theatre tix. This weekend we went to the Half Price Booth & they didn't have anything interesting, so we walked right to the Theatre we wanted to go to, and they had tickets there for that day's show. I think we were lucky. I HIGHLY recommend The Boy From Oz with Hugh Jackman. Get tix on left side downstairs (Mrs Marc will like it best there!).

LGA to Midtown is a flat fee of $45(plus tip). It will be very crowded for 3. I'd recommend a car service, but I cannot recommend one as I have not used one there yet. From Pier I would definitely use a car service. (If you find a good one, let me know).

Restaurants - too many to think of one for now. Where is the Hilton? Can come back to you on that later. If you look English Pub style food, the best Shephard's Pie is on 11th Ave at around 50th - The Landmark Tavern. very homey feeling, and "comfort food."

And I also highly recommend Doug's cousin's place. It is down in Soho area, so it'll require a cab. Be careful of those Pietini's. Dessert style martinis. It is like Candy with a Kick!
If Doug's not around, I am pretty sure we will be, and we'd surely go back there again. The steaks are fantastic too. Dylan Prime is the name of the place.

I hope I was some help to you.
Anything else - fire away.