Is it permissible for a person praying alone to pray behind the row, in the event of repeated breaking of ablution due to passing wind, in order to facilitate going and returning from ablution?

If you are afflicted with chronic flatulence ( سلس الريح), it suffices for you to perform ablution once for each prayer after its time has begun, and whatever is emitted from you will not harm your ablution. However, if you are not afflicted with it (which is the apparent case), then you must perform ablution every time it is nullified, even if you are in prayer.

As for praying alone behind the row: Imam Ahmad deems it invalid based on the hadith of the Prophet, peace and blessings be upon him. The majority of scholars, however, consider it valid, though disliked if the isolation is without excuse, and without dislike if it is due to an excuse.

Shaykh al-Islam Ibn Taymiyyah considers it valid for the excused person but not for others. It appears that your passing in front of worshipers is not an excuse that permits praying alone behind the row, as the Imam's sutrah (barrier) serves as a sutrah for those behind him, and you can stand in the back rows.