Good lists! Boy, do I hate #1 on your first list! I still sometimes catch my TKR leg on the frame when getting out, especially on the passenger side. That is one good thing about having a temporary handicap permit. I don't use it all the time, but in parking lots with spaces that are narrow, I do. Handicap spaces have extra room for opening the doors--yay!
Good idea, to use the front steps rather than the garage ones. We also have shorter front steps, and that's where I practiced until I could more easily do the flight up to our second floor. It sounds as though using your cane when doing them is important, at least for now. You may not have to use it for long until your "step muscles" strengthen up, but that pain you've experienced without the cane probably isn't ideal.
And now for a question, just because I'm curious! Re #4: How DO you prop your foot up on your cane? It sounds quite inventive. I graduated right from a four-wheeled walker to nothing. My sister-in-law gave me her cane, but it had the most awful, sticky handle, so I never tried it.
If you are thinking about using your cane more often, I would try it. Your brain may have a good reason for making you think of it. You may find yourself being more active, trying more things, etc. Having it with you doesn't mean you have to use it constantly, right?