Recruit a Friend gets you triple experience (or 200% extra, since everyone gets 100%), for quests and kills from levels 1 through 60th. Ignoring the granted levels or cascade granted levels, that is roughly 1/3rd the time from 1st to 60th. Even with RAF, you only receive normal experience as far as exploration goes.

Boosting will still be the best method to level. If boosting was better then questing with 3x the instance exp's vs 3x the quest exp's, then 1x both type's of exp's will still favor boosting.

The heirloom shoulders and heirloom chest will help out quite a bit.

Many people have managed to level teams, without RAF or prior to RAF being offered. It is doable if you want, and financially speaking that's probably the best route to take. It is a question of value of time versus cost of accounts/transfers.

Honestly, I'd personally bite the buck so to speak. Since you already have 8 accounts. You can RAF from say A and B, which will get your four accounts with faster leveling speed. If you care about the mounts, pay for the new accounts with game cards. If you're going for the best bang for buck, just pay for one month each on the new accounts, which credit the existing accounts with a month of play time, for a net break even. You'll still be out the price of two accounts (classic or battlechests if you want Draenei/Blood Elves), and the price of transfers.

Even if its 60 days after forming a B.Net account for transfers, you can wait that time easily. If you want to focus on your new team(s), then just pay the subscription for the two new accounts, two existing accounts and whichever account as the 5th toon for those teams. Once the 60 days is done, you can throw the accounts away, after the transfer.