1 Yes you can install it in ibays, but (don't you hate buts

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You will have to installit PN to be used in intranet mode or session will fail - users won't be able to login to the PN website.
If you use virtual hosting and configure each ibay with domain name you'll be able to avoid running PN in intranet mode.
There is few more CMS that you could use and don't have this limitation. The best one (and easiest one to install and maintain) is myphpnuke. Comunity is almost as big is PN and it's a lot faster than PN. - Good luck
2 I'm not sure on this part, therefore I'm not going to suggest anything. I'm sure someone here will be able to help you.