How long for 2nd proof with bread making?

It will not proof in the fridge. The cold climate will slow the activity of the yeast which is referred to as "retarding". If left in the fridge for multiple days the bread will sour and will change flavor. This is sometimes favorable and sometimes not. Retarding a bread for 3-4 hours shouldn't affect the flavor that much but you will still need to carry out a second proofing.

You can always retard and then proof but never proof first and then retard. This will cause the bread to fall (deflate).

As far as how long to second proof... Follow the same guidelines as the first proofing. Double in size!