Staying in Panglao you might be able dive with a good shop :
- Balicasag (full day trip) worth at least 2 trips
- Local Alona/Doljo walls and macro
- Pamilacan island (full day trip)
You've already covered 5 days diving.
Siquijor might be a too longish trip, you wont be able to dive for the transfer day.
If you REALLY have itchy fins, Cabilao would be your best move from Panglao, it takes less than 2 hours to transfer by car, hence you could still schedule late morning and afternoon dives if you travel early.
Better plan Panglao as a second spot, the airport is located 20 minutes drive from anywhere on the island.