According to this it sounds like 32 bit only for you.
Basically if you have a 64 bit proccessor then you may be able to, the early ones had some issues with Windows though.
Now whether or not there are work around's I don't know, I'm not up on my "bits", so you may want to search around on the forums to see if it can be done.
Supposedly yes, check out this. When using Disk Utility you MUST burn it at the lowest speed posssible.
W7 bootable USB flash drive is only supported on the latest model though.
According to your 10.7 Installation and Setup guide you should be able to.
Probably not but check anyway. Check here to see if you have the latest Firmware updates.
Your options are all listed here?