Learn English – Is the plural of the electronic mouse “mouses” or “mice”

I don't know if there are hard and fast rules about this. With mouse it seems to be that the accepted plural is mice, but if you're talking about a computer mouse you can use mouses or mice, so you'd be safe if you always used mice

Merriam Webster:

plural also mous·es : a small mobile manual device that controls movement of the cursor and selection of functions on a computer display

Oxford English

2 (plural mice or mouses)a small handheld device which is moved across a mat or flat surface to move the cursor on a computer screen.

As far as geese are concerned, I had thought they were always geese, but apparently there's also:

3 (plural gooses) a tailor's smoothing iron.

But the plural of tooth is always teeth!

Since iPad 2 is the brand name, the plural form would be "iPad 2s". A search for "iPad 2s" reveals over 500 hits while "iPads 2" yields only 80. Normally I don't care much for Google search results as an indicator for grammar, but in this case it appears that many of the "iPad 2s" hits are from official vendors and reviewers. However, there is enough room for doubt that you are probably fine spelling it how you like.