Must the prayer be repeated if the worshiper accidentally catches sight of someone else's 'awrah without intending to look at it, and must ablution and prayer be repeated for one who suffers from urinary incontinence if something escapes them after they had held their urine before the prayer?

Merely seeing the private parts of others does not invalidate prayer or ablution, as there is no legal text indicating that. As for urinary incontinence, if the urine flow stops for a portion of the prayer time, one must wait for it to stop. However, if the flow is continuous throughout the time or stops only for a short period insufficient for performing prayer with complete purity, then performing ablution for each prayer time, along with taking precautions, is sufficient. If it is not incontinence but rather frequent urination that can be controlled, then everything that exits necessitates repeating ablution and washing what it has touched, bearing in mind that praying while holding back urine is disliked (makrooh).