There are no axial forces and negligible loading so press fit on shaft and/or into part B could be ok. For ease of assembly/disassembly I'd prefer it to be press fit in part B, maybe with Loctite in which case I could probably dispense with the lip and make part B thinner, e.g. the width of the bearing. Would still need to retain on shaft to ensure registration against other parts in which case a spacer and circlip would would work ok. Relying on press fit isn't something I consider 'best practice' as a rule but here it might be ok.