GK - sounds like you're not having fun - the mysterious change in current would bug me.
You might try disconnecting the connector to the lamp and then testing that and or the trunk lid/switch to see if the current changes.
See this thread for the connector location:
Trunk Light power connector ident
This circuit does have in input to the Alarm - in the schematic in the link above, the box identified as F34 is a feed to the Alarm, if you have one that is.
Sorry I can't shed any light on the power window switch operation.