Do passing thoughts cause the emission of maniy or madhiy, especially if one does not dwell on them or feel lust as a result, and is the yellowish fluid seen after waking up and urinating, without recalling a wet dream or feeling lust, considered maniy?

We ask Allah to cure you of whispers. Fleeting thoughts do not necessitate the emission of anything. The default is that neither maniyy (spermatic fluid) nor madhiy (pre-ejaculatory fluid) is emitted unless there is certainty, because certainty is not removed by doubt. Your purity remains as long as you are not certain that something has been emitted. What exits after urination is usually wadiy (post-urination fluid). If the fluid is unclear to you, there are previous fatwas that clarify what is required of you. The one afflicted with whispers should adopt the easiest of opinions.