Oh-so-new, And Sweating Bullets Options

[gogh]

alright. i have an ibook g3 with cubase sx and a midi controller... i love using all the vsti's, but i wanted to explore the hardware side of things more, so i rounded up all my non-essential stuff, and managed to trade for a rackmount synth and a rackmount sampler. so... i dont even have any midi cords yet (buying some tomorrow) to hook up my controller so i can just see what the synth sounds like. i dont have a midi interface for the ibook, or an audio interface.

i was thinking of scrounging for a tascam us-224, because i 'think' that it is a mixer, a controller, an audio interface, and a midi interface all in one.
what i understand, is that i can plug the tascam into my usb, plug the synth into the tascam, plug the keyboard controller into the synth, send midi messages to cubase
then cubase sends the midi back to the synth as a 'ghost player' replicating my performance, so i run an audio line out of the back of the synth and return it to the audio interface in the tascam- and it can send midi out while allowing audio in to be recorded all at the same time?
did that make any sense?

will that eat up all the bandwidth of the usb connection? would it be better to buy a midi interface and an audio interface as two separate entities running on two seperate usb ports?

should i just buy an all-in-one usb midi/audio interface and a seperate mixer?

do i even need a mixer? can i use the cubase mixer just as well as a tangible mixer?

do hardware synths and samplers free up cpu power, so that my poor ibook isnt so taxed?

what is a daisy chain?

do i really need a second hard drive, if i wasnt using one for recording cubase before? does it slow things down to record to the ibooks hard drive? does the danger only apply to doing retakes, or does it still apply, even if you are recording only once and finally?

many, many thanks