can two devices share the same apple id

Yes.

According to this Support Article > http://support.apple.com/kb/HT4627

Your Apple ID can have up to 10 devices and computers (combined) associated with it.

Yes. If they are both your devices there won't be any problems. If they belong to different people, it's usually recommended to use separate IDs to create separate iCloud accounts (otherwise your data will be merged and you will share the same iCloud email account and 5GB of free storage), as well as for iMessage and FaceTime (otherwise you will get each other's text messages and FaceTime calls), while sharing the same ID for iTunes purchasing (if both people are in the same family).

I would think so because I have everything the same as a password and they al work.