1. I have older TiVos with older Starchoice receivers. I have a new 505, but haven't yet attempted to mate it with my TiVo.
2. That is correct for any digital only service, Starchoice being one of them. Dual tuners require analog cable.
3. It is transferred in an encrypted MPEG2 file format. It is easy to pull the file, and to remove the encryption, but it is a funny MPEG2 that needs processed to play on some things.
4. Yes, US purchased Series 2 TiVos will work fine in Canada.
Unless you want to hack the box a bit (newer boxes have security protection preventing system hacks), there is no reason to get an older Series 2 box. Series 1 boxes don't have the Canadian postal code entry screen, and the HD models are next to useless in Canada, as they have no digital OTA guide data for Canada, don't digitally work on Canadian cable (no Cablecards here), nor work with satellite or cable boxes.