I think some of the anomalities may occur because you're using to much of different manipulation stuff on the objects, where some of it may negate others, with the effect of some of them not working, giving other effects than desired... I'm to concervative to use lot of the fancy stuff, but here's what I often do:
When opening a form from my main menu, I hide the main menu and open the next form with acdialog.
When opening the next form from this form, I do exactly the same, hide the calling form, open the next with acdialog.
When opening a report, I hide the calling form, previewing the report. On close of the different objects, I simply set the calling form to visible.
Most of the versions of hiding the Access window that I've come accross, influences some part of "window" handling within Access (not all properties, methods... works), with the need for additional programming for that (reports!), so I don't bother using them.
I don't bother using the acdialog on reports either, because I need my apps to work on version starting with 2000 .. but you can for instance right click in the report to print. On small tests here, the acDialgo always brings the report to front, so I suppose there's som other code or properties (or database window thingie - if you're using something like mstrmage1768's faq faq705-2562, you did remember to turn it off for the report?) influencing.
As for showing only one program/icon/button in the taskbar, did you try the "Windows in taskbar" option from Tools | Options - view tab.
Roy-Vidar