Does the allied jungler at wraith camp receive shared experience when the enemy minions push and die to the turret in middle lane?
Short answer: Yes.
Experience from minion deaths is split between all champions within 1600 range.
1600 is actually a pretty long range. As an example, Nocturne's and Caitlyn's ultimates have 2000 range at level 6. Turrets have 775 attack range.
Short answer NO.
Minions are lane-only; MONSTERS are in the jungle (and dragon/baron). Monster XP is very localized BECAUSE of the problem your post presents -- it used to be possible to steal wraith XP from being too close in midlane. Now it's impossible, the range is very close for jungle XP (also to help with leashing at low skill levels!)