1) its a while since i did this, if I remember correctly you can set up a list of scales, (scales.txt rings a bell!?)
these are then activated by the scale talker, which is what stage is activating.
(the text in stage is actually not relevant, and can be edited, once your have setup the scales you want to use)
2) that doesn't sound like something you'd really want to do... it just takes a bit of practice to not do this :)
anyway, you can alter some of this behaviour for midi and vsts , by altering the matrix
3) sorry i don't quite understand, you mean you want a kind of pitchbend wheel behaviour?
(seems odd to want to move it off the main keys, as you wont be able to pitch bend polyphonically)
to use the bottom 2 keys you will need to remove the octave talker, (otherwise this will activate)
then you will need to map these onto a key group, and then finally send these to a midi converter, where you will be able to map the keys to pitchbend
anyway, Id recommend you come over to https://community.polyexpression.com , and ask there , as theres quite a few eigenharpers there, who might be able to give you some more advice.
I honestly doubt you'll find someone will to do the work for you... even if you pay, and its better to learn to do it yourself anyway, so that in the future if your ideas/requirements change you can do it yourself.