#1
looking for a halfway decent digital keyboard program for some tracks.

i dont have a real keyboard, and dont feel like purchasing one. i think a keyboard program would suit me better

preferably be able to both write a score that it'll play out, and push the on screen keys that it'll map out on the score. and have pre programmed effects that i can manipulate.

anyone got an idea or recommendation for a good one?
#2
Make a midi track of the what what you want to be played and then use a VSTi through a DAW. There are many free programs that can do these things. if you want more specific info about the process just ask.
Strange, It seems like a character mutation, Though I have all the means, of bringing you fuckers down, I can't make myself, To destroy upon command, Somehow forgiveness, lets the evil make a loss - Danger Mouse/Sparklehorse/Wayne Coyne
#4
Use Guitar Pro.
Write the part to be used for your VST.
Export MIDI.
Insert MIDI into your recording program, or DAW if you will. (Reaper, Cubase)
Use VST inside of said DAW.
Press Play.
???
Profit!

As for your OP, I don't believe anything like that exists.