I have come across two great sites with kind people who have simplified Primary songs, free to download. I know it must have taken them hours and hours to do.
There is D’Net Layton’s site here. She has made the songs very simple, included colour pictures from the Primary Songbook and has some pre-reading songs too (notes with finger numbers, not on the stave).
There is also Michael and Heather Smuthwaite who have kept the songs in their original key from the Children’s Songbook, added fingering and have a feature where you can listen to the song as well. Their site is here. They also have some simplified hymns and choir arrangements.
I don’t have a primary pianist called as yet, but I have someone fill in for me (except the one Sunday she teaches RS. She’d much rather be in Primary!). I have a student of mine in Snr Primary play simplified Primary Songs while Snr Primary is walking in to Opening Exercises, and our Jnr Primary is making their way back from having a drink and/or going to the toilet. We sing along with my student, which get the attention of the children. It’s a great confidence booster for her. It also gives our Presidency the opportunity to check that the children giving the talk, scripture and prayer are present on the day.