Depends, but the two devices have different dimensions. A neoprene (or other stretchy fabric) sleeve will likely fit OK, but I think most folio type cases will not.
The Lenovo K1 is 10.4×0.52×7.4 (WDH) while iPad 2 is 7.3×0.4×9.5 (WDH). The lenovo is longer by almost an inch so will definitely wont fit into any iPad 2 cases. In fact, based on our experience, its also too long to fit into iPad 2 sleeves. Your best bet is to get an 11'' sleeve. It should also fit well into cases made for Notion Ink Adam (10.6×0.55×7.5).
Yup, it definitely won't fit. Each device has accessories made specifically to their dimensions, try browsing through the web for specific accessories for your device!
They are not compatible, unless you modify one from ipad custom cases, but this need a lot of work. I suggest buy the one that fit your device instead.