If I send a copy of the disk, but it will already be processed to level 3, will I get money for it? I have already sent this signal, but without processing

I'm pretty sure sending any disk with green light will count. if it's a yellow light i don't think it counts.

if i'm not mistaken you're able to fulfill daily tasks using them, but trying to send it more than once won't give extra money for selling it

You can kind of get around the yellow light by reprocessing them, but if it's already lv 3 it will not give extra money. Pretty sure I've gotten money by upgrading early saved signals.