1. You can search around the forums for some hints, but I imagine the only way to know is for you to set up a server in the configuration you want. I have no experience to contribute.
2. All Linodes have a 250 megabit/sec outbound cap. This is mainly to prevent you from burning up your monthly transfer quota due to a misconfiguration or malicious activity. You can ask to have this limit changed, but you should have a good reason. There is no cap on inbound bandwidth.
3. If you consume more than 2 terabytes of transfer in a month (for a Linode 1GB), you can
buy additional transfer or upgrade to a larger plan.