Turned straight in a multi-way pot

CO is a nit running 12/9/AF3.5 (200~ hands); SB is a spewy aggro station who I've seen 3 barrel ace high on a very drawy board twice. He's @ 27/12/AF7.0 (60 hands).

SB's leading out/barreling range would include 6x, 8x, and possibly other low pairs/SCs. I figured I had little fold equity against him and the 3 other players in on the flop so I didn't raise, esp with the paired board. UTG has been extremely passive (21/4/.80) and I've seen him float overpairs. What can we assume CO's continuing range consists of? Low pocket pairs or perhaps suited connectors? I doubt he'd be limping pre with 88+. Would he call and not shove 44/88?

Board: 8s 6h 6d 4d

equity win tie pots won pots tied
Hand 0: 65.283% 63.19% 02.10% 485811 16116.33 { 7c5h }
Hand 1: 17.475% 16.13% 01.35% 123997 10359.33 { 88-22, A8s, A6s, K8s, K6s, Q8s, Q6s, J8s, J6s, T8s, T6s, 98s, 96s, 82s+, 76s, 62s+, A8o, A6o, K8o, K6o, Q8o, Q6o, J8o, J6o, T8o, T6o, 98o, 96o, 82o+, 76o, 62o+ }
Hand 2: 17.242% 14.50% 02.74% 111468 21100.33 { 88-22, A8s, A6s, K8s, Q8s, J8s, T8s, 98s, 86s+, 75s+, 64s+, 54s, 43s, A8o, 98o, 87o, 76o, 65o } (this may be a bit wide of a range for a nit though; imo it's usually low pockets more than anything)


PokerStars No-Limit Hold'em, $0.10 BB (6 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

Hero (BB) ($17.30)
UTG ($6.60)
MP ($20.30)
CO ($10)
Button ($36.50)
SB ($11.40)

Preflop: Hero is BB with 7, 5
UTG calls $0.10, 1 fold, CO calls $0.10, Button calls $0.10, SB calls $0.05, Hero checks

Flop: ($0.50) 8, 6, 6 (5 players)
SB bets $0.30, Hero calls $0.30, UTG calls $0.30, CO calls $0.30, 1 fold

Turn: ($1.70) 4 (4 players)
SB bets $1.25, Hero raises to $4, 1 fold, CO calls $4, SB raises to $11 (All-In), Hero ????