Jason,
I might not be able to fully answer Question #1a&b as I have not tried the bypass on my F900 yet. I am waiting to read more about the good and bad long-term results that other more technically proficient owner's have before I do. Although, I can answer #2, yes.
Even though you did not ask I will take a moment to tell you what to expect with a F900. Before I start I will make this blanket statement; I would do it again (purchase an F900), and I am a former owner of the AVIC-Z2.
The boot up time is pretty long (mine is around 45 seconds before the unit is full functional) but if you load a nice splash picture onto the unit it will at least look good while it is booting up. Also, the unit will start playing whatever audio was playing before you last turned the car off within 10 seconds, so if you are mindful before you power-off you can tee-up something nice to play and it will begin playing shortly after power-up while the system goes through its booting process.
My unit has good days and bad days; good days means it performs all of its functions near-seamlessly with a delay here and there. Bad days means it needs to be reset because it freezes (I have the latest firmware update) when too many buttons are pressed or options are excersized. It has more good than bad days.
The iPod connection through the hard wire sucks. This function fails at least once everyday and often a few times. This is my main complaint. Yet, the on-screen interface is so much better than the Z2's. If you learn to manage your playlists efficently it can be quite easy and rewarding to use the iPod.
Many people complain about the Bluetooth but mine works fine. No issues at all and people on the other end hear me clearly without an echo. Sometimes it does not recognize and display the name of a preloaded contact when they are calling in but most of the time it works. I do not like the way contacts are displayed in the library as I cannot tell which number is which (home, work, mobile, etc).
For some reason the HD radio presets are very sensitive to the touchscreen scroll so sometimes it moves two stations when I only wanted it wo move one station. Regular FM/AM seems to be fine. Another thing, the regular FM antenna must be functional to recieve the MSN Direct broadcast. This only comes into play if you were to unplug regular radio and plug in the HD antenna in its place. The soluion I used was a splitter to make both HD and FM/AM functional.
HD radio is cool because many stations have multiple broadcasts from which to choose but unlike the name, HD is not High-Definition, it is just digital. The HD interface was $119 with a $50 mail in rebate.
MSN Direct, I am supposedly in the coverage area but I never have any "bars" showing reception but my unit does have the MSN Direct hooked up and functional. People are blown away when I show them the weather, forecast, local movie times, traffic times, and gas prices. I do not use it that much though, yet. Still trying to grow accostomed to that information being at hand.
The DVD Playback is better and more user friendly than on my Z2. CD playback is pretty standard.
The navigation is dead on and I also like it better than the Z2's nav. Although it does not have as many viewing options I still like it better.
Although it has a more functional/friendly EQ it does not have the sound processing function that the Z2 had which is a minor concern. It does have amore robust subwoofer control and capabilaity than the Z2, which is nice.
I have only used the SD SanDisk for uploading splash screens. Pretty standard but a good splash screen makes quite a difference.
I would also like to give props to Pioneer Shallow Subs. Very impressive! People are amazed I do not have a giant sub-box somewhere.
That's all I can think of to have you prepared for your F900 experience. Hope it helps.