IOS for computers, yes.

iPads, tablets and smart phones, no.

Is there going to be a version for IPads or IPhones?

There has been nothing said about versions for phones or tablets. Most of these devices come with email clients installed. Why not use that?

The recent Firefox on iOS is not actually Firefox (like on desktop or Android) but is just a re-skin of safari with Firefox features like sync built in.

The Thunderbird community has its hands full enough as is in getting out Releases in Extended Support Release fashion for Windows, Mac OSX and Linux to be focusing on any mobile option say for Android or iOS.