Is there any taxi or mini van for a group of 10pax to xiamen millennium harbourview hotel?

I'm afraid there no such taxi or public mini van to hold 10 people. If you really wanna share a van, I suggest you book a pick up service in advance. I recommend you use the pick up service of Travel China Guide, whose email address is bookingtravelchinaguide.com
Also you can consult them about the cost.