Everything in the overhead is locked unless for some reason my laptop bag can't go under the seat. (There's no way to lock my laptop bag--the one flaw in an otherwise good bag.)

Passports and cash are always on my body, never even under the seat.

Seatbelt unless I need to get up. If I'm trying to get some sleep it might be quite loose.

Shoes unless we are at altitude.

I note where the exits are--not by counting but by what is around them. Counting in an emergency would be hard anyway. I do not worry about which is closer--in practice you're going to have to go with the flow. Swimming upstream to a closer exit is almost certainly going to take longer.