i386 vs. amd64

[Aryeh Friedman]

Ever since 8.X (my system is now 9.1-RC3 [done via csup]) been using
i386 with the following main ports:

x11-wm/xfce4
www/firefox
www/linux-f10-flashplugin11
editors/libreoffice
www/tomcat-7
www/apace22
devel/aegis (I am the maintainer)
devel/fhist
devel/cook
java/openjdk6
emulation/virtualbox-ose (and additions)
print/cups

I have avoided amd64 in the past due to some or not all them working,
but want to switch if possible because PAE seems to be broken now on
i386.

So I have the following questions:

1. Will all the above ports (and their dependencies) work on amd64?
2. Is there any way to do a in place switch to amd64 or do I need to
rebuild the system from the ground up?
3. In general is amd64 now as capable of handling ports and such as
well as i386 does?