Yes and yes.

When I lived in the UK, it was always clear that tortoise is terrestrial and turtle is marine. I never heard anyone confuse the two. But in the US, it's not uncommon by any means for a tortoise to be referred to as a turtle. I would be prepared to stake a small bet, in fact, that it's called a turtle in the US more often than it's called a tortoise. However, as is the case in the US where "monkey" is nearly always said when "chimpanzee" is correct, when you dig deeper and get into a discussion it soon becomes clear that the speaker is aware of the difference, and just talking from (bad) habit.

Yes, right in calling. To be honest, I didn't think about it. I just copied, pasted and accepted the text as it was. It was only later that it occurred to me that we were dealing with tortoises.

Yes, but, as Steve found out a few hours ago, it appears that calling a tortoise a turtle is not technically wrong, so maybe you were right in (in?) calling them turtles.

Take a look at this: https://www.italki.com/discussion/122863. After dozens of comments on the post, I finally realised that they were tortoises. A turtle wouldn't mind getting wet.