Specifications:
Package Included:
Yes it will work, with the AC adapter, it is convenient and safe to charge more than two controllers at one time with your PS3.
The power adapter is needed only in case where the power supplied by a single USB port. With multiple power hungry devices running, the additional power provided by the adapter is sometimes required.
There will not be any problem, this is because the USB HUBs have got their own controller ICs that manage data transfer. Also USB 2.0 speed is fast enough to control your usb speakers and mouse at the same time.