Q: Can I use one photos library on an external disk (synced with iCloud) sequentially with different macs (same account) and/or with different accounts?

I am very happy with the new iCloud fotos. It works very well with my MacBook, my iPad and my iPhone. I saved the library with the originals on an external hard disk.

Since we share two MacBooks in our family I would be happy to use the same library with the same account on the second MacBook otherwise I have keep two similar libraries. Will this cause any trouble?

The other question would be if is it generally possible to use the same library on the hard disc with an other account (e.g. the account of an other family member)?

I am aware that this library would then be synced with the other account as well - which would not make to much sense, but the question is if this could cause any problems?

Looking forward to your answers.