I got tired of searching 10 different threads for these stats so here it is, the combined list of endgame pet stats (Widowmaker is 34DD and likes long walks on the beach as well)
Engineer (Buffs - +446 AR, +130 AR, +280 AR. Items - +40 AR +4000 HP)
Widowmaker
HP: 37125+4000 = 41125
AR: 2590+896 = 3486
Ravening M60
HP: 23203+4000 = 27203
AR: (3470, 3470, 3470, 3467, 3459) + 896 = (4366, 4366, 4366, 4363, 4355)
Crat (Buffs - +133 AR, +25 AR, +600 AR (bot only), +3000 HP (bot only). Items +40 AR +4000 HP (bot only))
Carlo
HP: 55687
AR: (2229, 1560, 2239, 2239, 2245) + 158 = (2387, 1718, 2397, 2397, 2403)
CEO Guardian
HP: 34663+3000+4000 = 41663
AR: 2014+798 = 2812
MP (Buffs - +500 AR)
Rihwen
HP: 55687
AR: 2261+500 = 2761
Sources: various threads, mostly based on work by Malaxia, MrStabby, Kuz. If there are corrections, do tell!