I'm a GTD user, so I look at these things from that perspective. The GTD workflow is summarized as Collect, Process, Organize, Review, Do. In your description, I see a lot of Collect, a little Process and Organize, a bit of Review, and not much about Do. If I do a bit of reading between the lines and extrapolation, I can imagine how the rest of your process works, but detail would be better.
I suspect if you were to characterize your system it is probably closer to Mark Forster's "Do It Now" than GTD, using a single list of tasks and working from there.
I'm having a bit of cognitive dissonance between your #2 and your final paragraph. I don't understand how you move emails from your inbox to your task list, if you are using the inbox as a task list.
Using an email inbox as a task list I know works for some people, but would not for me. The first problem I see is offline access. How does one work through a list of tasks when offline? You could print to paper, but that's an extra step that could be avoided with a different technology. I suggest you consider using a list application. There are many around, you will probably find you like one better than the others. Use what suits you and is available offline. I use RememberTheMilk, the iOS and Android apps work well when disconnected and sync seamlessly when reconnected. Another option might be Evernote, which also syncs well from my iOS and Android devices and has just added a reminder feature. It is able to receive entries via email, so your workflow might not change much, as you forward from your inbox to Evernote as you process your incoming tasks.
Another thing that concerns me about using the inbox as a task list is differentiating what is really new from what I am able to work on right now. I really don't want to see my yard work and gardening tasks when I'm ready to sit at the computer and pay bills, only to get distracted by the email coming in from my siblings about the upcoming family reunion. When the task list is separate from the email inbox, the distraction risk is greatly reduced.
There is also an odd sense of relief from following an Inbox Zero practice. Knowing my inboxes are all empty is an amazing stress reducer. It means that all current input has been processed, and is somewhere in my system waiting to be worked on. If your inbox is also your task list, I don't see how you could get the same feeling.
I like your solution for ticklers and reminders (#1). I do the same kind of thing with RememberTheMilk, with less investment in writing my own tools. I use recurring tasks with a #tickler tag, and a filter on my working lists that hides anything with a future due date. (I don't use due dates as deadlines, I use them as "show me" dates). The net effect is very similar - new tasks appear on working lists at regular intervals. RTM offers one additional feature over the crontab, in that it can automatically repeat a task at some interval after it is completed. So rather than define a task for "every week" and have more than one of them in your list if you didn't complete the last one, you can define the task as repeating "after 1 week", and it will reappear a week after it was last completed.
Bravo for using a trigger list, and the home walkaround. I find them both useful, and don't do either as often as I think would be optimal.
For your #5, capturing ideas, I've tried voicemail, voice recording, email, evernote text, evernote photo, evernote voice recording, direct entry to Remember The Milk, and probably some other technologies I'm forgetting. What works best and fastest almost all the time is paper and pen. I carry a small notebook and pen all the time, and capture ideas there. The overhead to get the handheld device out, turned on, and the right app started is almost always more than taking pen and paper out of my pocket and writing the note. I would like the technology to work for me, but it just doesn't. You might think about moving to low-tech capture, and experiment with that for a couple of weeks to see if there's any friction reduction. If what you're doing is working for you, great!
Thanks for the opportunity to comment!