Aslamo Alikom
I enjoyed reading these scenarios and was calling back memories when i saw others (sometimes me ) doing one of these things.
However, i would like to comment on one case
The Reckless Lane-Changer: A Reckless Lane-Changer is a person who was unable to join at the start of the prayer, but still wants to participate. When entering a highway, there are specific guidelines as to where, when, and how you are to merge onto it; you cannot simply swerve over when you wish! Likewise, when joining the congregational prayer which is underway, a person cannot join during Sujood, Tashahud, or just any other time that one sees fit.
From what i know a late comer should join the prayer at any point without waiting for Imam to stand up. Of course the raka'h will be counted only if he/she joined before or during rukoo.