How fast will he run? Lagat's 62:00 half-marathon PB from Houston 2018 is worth about a 2:12:00 according to John Kellogg's conversion chart, but obviously NYC is a hard course. Meb Keflezighi has the US Masters record at 2:12:20.
Chris Chavez has an interview with Lagat here:
https://www.si.com/edge/2018/08/23/bernard-lagat-new-york-city-marathon-debut
Update: NYC has come out with its full men's elite field, listed below.
Abdi Abdirahman, USA 2:08:56
Juan Luis Barrios, MEX 2:10:55
Shadrack Biwott, USA 2:12:01
Ryan Blood, USA Debut
Florent Caelen, BEL 2:12:51
Mizael Carrera, PUR 2:21:50
Andrew Davies, GBR 2:15:11
Chris Derrick, USA 2:12:50
Lelisa Desisa, ETH 2:04:45
Scott Fauble, USA 2:12:35
Senbeto Geneti Guteta, ETH 2:11:12
Nicholas Hilton, USA 2:16:20
Geoffrey Kamworor, KEN 2:06:12
Birhanu Dare Kemal, ETH 2:12:21
Shura Kitata, ETH 2:04:49
Bernard Lagat, USA Debut
Eric Loeffler, USA 2:16:50
Jonny Mellor, GBR 2:12:57
Alex Monroe, USA Debut
Harbert Okuti, UGA 2:17:30
Tim Ritchie, USA 2:11:55
Alphonce Simbu, TAN 2:09:10
Scott Smith, USA 2:12:21
Festus Talam, KEN 2:06:13
Fikadu Girma Teferi, ETH 2:09:34
Chris Thompson, GBR 2:11:19
Tamirat Tola, ETH 2:04:06
Daniel Wanjiru, KEN 2:05:21
Jared Ward, USA 2:11:30