Uncapped 2/5 game

This game started a few hours ago and I've been playing snug. I showed down one hand and I lost with AA. Seat 1 was aggressive in position. Seat 3 was LAG, they called shove preflop with AQ twice.

Hero: $800
Seat 1 HJ $1000
Seat 3 Button $600
BB is villain $750

I limp UTG with KcKs assuming seat 1 or seat 3 is going to raise.
Folded around to seat 1 who raises to 20, button calls, sb folds, bb 3bets to 100. I three bet to $300 folded back to the BB who flats.

$642 in the pot.
Flop is 245 clubs

I shove the flop for $500.

Questions:
1. Is the four bet sizing appropriate? Thoughts on bet sizing relative to stacks? Do I ever ever flat?
2. In hindsight, I was thinking I could down bet the flop to $150and welcome all over pairs that doesn't have a club??? Shove all turns...only afraid of non club Ace and non club 3.

Why did you tell us about the Vs who folded pre and not BB?
4-bet is prob fine. Flatting and playing the same size pot but 4-ways makes no sense to me.

Flop is fine with under a PSB left.

Ah, great point! BB hasn't been out of line nor has he showed down any hands. Seems to be a snug player.

I feel like your not going to get a call unless your behind, basically you pushed out every possible "bluff". I woulda bet 150 and drug them along. Especially since you hold the Kc.

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You are not folding. How you decide to get money in pot is really up to you.

$200 on flop
Shove turn is fine.

Shoving flop is fine.

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