devices owned by a plug-in

I'm trying to understand the preferred way a plug-in can create and find devices it owns. My plug-in will have about 10 devices.

1) Should it create one root device with 10 child devices or 10 root devices? With 1 root device, the plug-in has found all of them once it finds the root device.

2) How should the plug-in determine if any devices exist that were previously created by the plug-in? It looks like this is based on the name of the plug-in, so how can I ensure my plug-in name is unique? If I pick a name like 'weather', it seems the system will not be able to run another plug-in someone calls 'weather'. I see where the plug-in should not use the address or code fields to attempt to create a unique device name. I envision ending up with some plug-in's that I don't publish (not useful to anybody but me) and some plug-in's from the community. Thus, HST can not be the gatekeeper to ensure unique names.

Thanks for any insight.