Is the Hajj valid for someone who performed the Farewell Tawaf while suffering from urinary incontinence, and does not know whether his ritual purity was broken or not, due to the presence of a tissue that prevents him from feeling it?

The questioner's prayer and circumambulation are valid. His ablution before the Maghrib prayer time, even though he suffers from urinary incontinence, does not affect the validity of his prayer and circumambulation, as long as nothing invalidating ablution occurs. This is because the original state is the continuation of ablution unless one is certain of something that invalidates it.