The bitrate of DVCProHD is 100 Mbit/sec Thats 15 MB/sec
The SATA drives easy push 30 MB/sec, even more if you RAID them.
So the playback is no problem.
In FCP you have alot of presets, just choose one.
The best thing is to go native and capture over firewire from camera, that way you don’t even need to use the capture card.
Yes, you can go component, composite or SDI.
You need to set up your AJA Kona controller to the inputs you want to use. It only “listen” on the inputs you say it would. (and outputs)