A couple more questions:
Is it possible to have a P2P account & a F2P account under the one Battle.net account?
What do I need to do to be able to create a Death Knight & Monk classes on the F2P account?
Thank you!
1) Yes, you can have a f2p WoW account linked to your p2p WoW account. They will be under the same battle.net account, and you will use the same login and password to log into both. There is just a little popup where you choose which WoW account to use at login.
If you already have a p2p, adding a f2p account is easy. On the account tab of your battle.net page, you can create
one starter edition account that will be automatically linked to your p2p account. To link a new p2p account to an existing f2p account requires a phone call to Blizzard Billing Support @ 1-800-59-BLIZZARD.
2a) As a f2p, you cannot create a Monk. You need to have upgraded to MoP to play a monk, and your f2p account is not upgraded. If you upgrade it to MoP, it is no longer a f2p account.
2b) You cannot, anymore, create Death Knights on f2p accounts. For a while there was an undocumented feature where one could make a DK on a certain server, unlocking the ability to make DKs on that account. This feature has been (partially) removed from the game. If you were not able to take advantage of that opportunity to make a DK on said realm before they removed that feature, you will not be able to make DKs in the future. The DKs made in this way were one-time-use only, as soon as you logged out, that character was locked, and unplayable.
Not a big deal really since you can't play lvl 55 DKs (mimimum level for a DK) in the f2p 20-24 bracket.
TL;DR: F2ps can't make Monks or Death Knights. To link accounts, call 1-800-59-BLIZZARD.
p.s. Be super-nice to the people on the phone.