No BB's have ring and vibe at the same time as I understand it.
The best thing to do is get used to the fact that you have to keep your phone close by so you can feel the vibration before it starts to ring.
As far as ringer volume, that was a big issue for me as well. What you need to do is use an MP3 as a ringtone that has a high volume level. All of a sudden you will start noticing when your phone rings. (my general ring tone right now is that crazy loud cresecendo-ing part of Manfred Mann's Blinded by the Light....
As for multiple alarms:
http://forums.crackberry.com/f52/multiple-alarms-5073/
Calendar syncing I don't know about. My work calendaring system is non-standard (it is web-based rather than and outlook or exchange server type app). As such, I haven't even bothered to try to figure it out.