Guests staying in Tuckahoe - we highly recommend HPN. Guests staying in Bronx or Manhattan - LGA, preferably. Of course check all NYC area airports for the best deal, but be aware that Uber/Lyft from EWR or JFK will cost substantially more than from LGA. So, it may be a wash in the end. Additionally, public transportation from LGA is considerably less complicated.
Text Lindsey personally. She's got a good handle on Bronx and Manhattan geography. And, if she's unfamiliar with the specific neighborhood, would be happy to make a quick drive to vet it for you.
The ceremony will be outdoors. Weather permitting, dancing will be as well. I'd suggest a shawl, wrap, or jacket of some sort in case the temperatures are on the cooler side. It also wouldn't hurt to bring a small umbrella.