Is it obligatory to cleanse a drop of urine and drops of blood that fell in the bathroom, with doubt about the impurity transferring from them to other parts of the house, and is this considered a form of waswas (obsessive whispering)?

The default status of the bathroom floor and slippers is purity unless their impurity is known. The drops of blood on which water was poured are sufficient (for purification). As for the drop of urine, water should have been poured over it, but impurity is not ruled except by verifying its transfer. A small amount of impurities is entirely forgiven by some scholars, such as Ibn Taymiyyah and Abu Hanifah, and this is the preferred opinion for someone suffering from waswasa (obsessive doubts) to alleviate hardship and difficulty. It is unlikely that impurity transferred from those drops, and the cure for waswasa is to disregard it.