1. Assume you have 1/2 tank of gas. Should fuel flow out of both of the pitcock outlets? Doesn't matter if it is in reserve or regular. Fuel flows out both outlets.
Yes. But, if you are watching it, gravity will make it look like the first exit from the log dominates. But, once flow stops at the first (from a filled pipe) the second one will flow as the first.
2. I have a small inline filter on one of the fuel lines. Is that original? seems silly to have a filter in that location downstream of the pitcock filter.
The stock ones have a filter in or on top of the petcock. (depends on model) No in-lines. I'm one of those that think the stock filters in proper working order are all you need. Others disagree, but can't explain the physics of needing two (or more) filters for the fuel. However, for whatever their reasons, they seem to be happier people with the arrangement.
Cheers,