I think most tuition centers conduct P1 preparatory classes. I dont't think there any tuition center that does an all-in-one. Learning Point at Thomson Plaza is quite good.
My gal started KinderArt in NAFA since she was in K1. But the queue is very very long. Usually registration is only open to waiting list after they filled the priority list for existing students' siblings. Reg is in Nov of each year, waiting list will close at least 1 year before. I queued for 1.5 years before I got a slot. She has been moved to the elementary class for Pri sch this yr.
I think NAFA conducts very good classes for children, not too expensive too. I pay $380 per sem, material cost is approx $70 for each yr.
Music wise, she started JYC in Yamaha at age 4. It is basically keyboard at that age. The teacher matters alot so do ask around for recommendations.