Not a sales representative, but here are my short answers:
1) All DreamHost servers are located in the United States.
3) 1 gigabit per second, multiplied by one month, is about 328 TB. More than that is physically impossible over a 1 Gbps network connection.
(We'd appreciate it if you let us know ahead of time if you plan on using this much network traffic.)
4) No, I'm afraid not. Sorry.
5) Yes, so long as they are are in compliance with our Acceptable Use Policy. In particular, if you intend to host Flash games, you need to make sure that any games you host or embed in your site are licensed for that use. (Simply copying games from other sites is a copyright violation.)
6) Yes. Any databases hosted in any location on your account, including a dedicated server, can be connected to from other machines on your account.
7.i) Yes, but it will take some significant custom development work.
7.ii) Neither. Any content hosted in DreamObjects must be on a separate hostname from your main web site, and is not stored on your web server.