A:AnswerYes, you can and must remove it to use a charging pad. I would recommend a magsafe charging pad that will hold your phone in place or one that secures your phone.
A:AnswerAs far as I know none of the iPads, pros, or mini has MagSafe. But you can get MagSafe styled cases that might work adding the feature.
Also no it won’t hurt it otherwise it would damage iphones too. But they aren’t built with MagSafe magnets. The iPads have magnets elsewhere for the apple keyboards and cases.
A:AnswerYes, it will be strong enough as long as you have a MagSafe case or no case at all. MagSafe friendly cases make the connection much stronger, but they are not needed.