With absolutely no reads I think you can fold this and wait for a better spot. Only 6BB invested and UTG might come over the top. You could flat here but you can expect another big bet on the turn which you'll probably end up folding to anyway...

What you can do if you really want to get info is try searching for a player's name and seeing how many tables they are playing. That might give you a stereotype you can temporarily use. Also, whenever someone is playing with a short stack they are a donk unless proven otherwise in my book at these stakes.

With reads this becomes a simple question. Personally, I think this is why my bankroll is always really deep. I think the CO min raise is something that is isolating UTG, and could be happening with a draw(89) there or TP. I was almost thinking raising really donkish here...say to $6 might give you enough information at this level depending on what CO does. But, I like a raise(normal) most.

I am not sure you would expect to get another big bet on the turn here by CO.

Do you usually raise 4xBB+1 for every limper at NL20? I think I would have raised more maybe 8-9xBB, and try and entice UTG to maybe push here, and get rid of CO preflop.