I was with you until tortoise. US English speaker here, but I have literally never heard anyone say “tor-toys”. I think I’d have a serious moment if I did. Is there some link you can throw our way to demonstrate the point? YouTube?
For what it's worth the Oxford English Dictionary lists /ˈtɔːtɔɪs/ ("TAW-toice") and /'tɔːtɔɪz/ ("TAW-toiz") as alternate pronunciations in British English. This appears to be the result of a revision made to the entry sometime after 1989. (The public-facing revision history is not very precise.)