You've got two defog users.
Personally, I would switch out defog and parting shot on silvally for better coverage. Thunderbolt, flamethrower, icebeam, and surf is pretty good, but you lose all your utility. You could get rid of defog on togekiss, but its pretty reliable. If you do, switch it out for soft-boiled. Its the bulkiest pokemon on your team. The longer he stays alive, the better.
You could also change heat wave for flamethrower. It has the same chance for a burn, and higher accuracy. However, steel types will kill him. I suggest air slash and shadow ball.
You could choose to keep both, but I think its a waste of a moveslot.
Give togekiss softboiled.