Editing 720p on Older Core 2 iMac

[cw4u]

I'm trying to get my gear list together for our student choir tour this summer and was wondering if a Core 2 2.2?? w/4GB 667mhz ram will work? I believe it has a 500gb 7200rpm drive in it and I'd be bringing a 500gb firewire 400 drive to render projects to. I'll be using Final Cut Express to do all the editing.

I'll be using my Canon 7D and a Kodak Zi8 for all videos captured. Should I just capture in 720p?

The video projects will just be a daily report of what's we're doing that is about 5-7 minutes. And a cumulative video that I'll upload to our church that will be shown the Sunday we are gone. (3-4 minutes) The daily reports won't be too intensive except for some minor green screen (20 seconds) work.

Basically the schedule is:
11:00-12:00am - Record Daily Report (Import morning/afternoon clips)
12:00 - 1:45am - Import daily report, edit
1:45am - 3am - Render and upload videos to YouTube/Vimeo
3am-6am - Sleep!!

I just have never really worked in HD that much so I don't know how long the conversion to AIC or final render will be. Should the time allocations be enough to edit, render, and upload?