A cyclical vibration from the front may be a slight wheel imbalance both sides phasing in and out. My Plus 4 does this.
The slight rocking of the wheel you describe which vanishes with brakes applied is the bearing, but not serious. It may be possible to go to the next flat/split pin position to take up the slack.
I need my P4 balance checking, and I have to nip up the bearings at some point.
