Is it permissible to dry oneself with tissues after cleaning with water (istinja'), or to use wet wipes to remove residual traces due to dry stool? And are the drops of water that splash onto the thighs and clothes during istinja' in Western-style toilets considered impure (najis) or pure (tahir)?

It is permissible to dry the area of istinja' (cleaning after relieving oneself) with tissues after purifying it with water. However, if the area has not been purified with water, it is not permissible to use tissues alone for istinja'. If the water separates from the impurity after its removal, it is pure. But if it separates from it before its removal, it is impure. As for one afflicted with waswasah (obsessive doubts), it is permissible for them to adopt the view that water does not become impure unless its characteristics change. The water that has touched a ritually impure area is, in principle, pure, and its impurity is not ruled upon except with certainty.