What is the ruling regarding my prayer, when my qiblah is directed towards my sleeping friend's bed, with no barrier between us except my own bed? And what is the ruling regarding my ablution when I repeatedly utter bad words to myself during it? And does one who curses the religion – Allah forbid – have to perform two rak'ahs of prayer?

There is no harm in praying with a sleeping person in the direction of the Qibla, as the Prophet, peace and blessings be upon him, and Aisha, may Allah be pleased with her, did. Obscene speech during ablution does not invalidate it, but it is better to remember Allah and to be keen on refraining from useless talk. If you are not certain that an oath was taken, then it has not occurred legally, because the default is that no oath has been sworn until certainty is reached, and an arising doubt does not cause harm. Fleeting thoughts and whispers are not blameworthy unless acted upon or spoken. Insulting religion is truly disbelief and apostasy, but fleeting thoughts and whispers are not blameworthy, and one must divert their thinking from them and seek refuge in Allah. Two rak'ahs of prayer are not required due to such thoughts.