Hi, welcome to NinSheetMusic!
This looks like a nice rewrite of the track for a beginner performance, the left hand isn't very demanding to read, there are fingering guides, and it all fits onto one page. If your kid is familiar with dynamics, it might be worth putting a mezzo forte (mf) on the sheet at the start.
As far as crediting mastersuperfan, I think you might be being too generous in your credit to him haha, only because looking at your two sheets, I can see it is based off of it, but he didn't outright make the arrangement you have. Maybe change the credit to "based off an arrangement by mastersuperfan", but feel free to credit yourself in someway also.
I'm actually not familiar with the notation software you mentioned, but most people use Finale or the free version and very limited, Finale NotePad along with MuseScore (by converting MuseScore files into Finale). This standard is due to the fact the site had kind of zeroed down to just Finale files, plus PDF's based off that file and a midi as well. Both Finale NotePad and MuseScore are free, but the process of getting a MuseScore sheet to be a Finale one is a bit quirky to say the least, but thankfully there are guides that community members have made to make it work.