[LAU] Seq24 and general MIDI questions

Hello, The MIDI world is new to me so forgive me if some of these questions are kind of dumb. My overall strategy is to get my beats, keys, and basslines down in Seq24 using Zyn, amSynth, and Hydrogen, then send the midi tracks to Rosegarden for addition of audio and further tweaking, then mix the whole thing down as audio in Ardour. Does that sound about right? 1) Is it possible to send a Seq24 song track-by-track to Rosegarden? How? I have been bouncing all the tracks to one audio track and mixing in additional audio tracks in Ardour, but that seems like a sub-optimal way to do it. If I could get it in Rosegarden in midi form, then I could fine-tune the midi tracks even after recording audio, right? 2) Where can I get additional instruments for Zyn? The ones that come with it out of the box are OK, and it's great that you can edit them and roll your own instruments. Right now I just want a nice natural sounding bass, and the ones that come with Zyn are not cutting it. Anybody know where I might find such a thing before I spend five hair-pulling hours making my own? 3) Can Ardour be used as a midi sequencer? Is it possible to put a midi track in Ardour or do you have to send it as audio? Many thanks in advance.