Hi --
Thanks for mentioning these new keyboards.
The E30 is definitely for young kids. Barnyard animals above the keys where you would expect to find percussion instrument icons?
The F30 is targeted for older kids -- maybe 8 years old? It's a mini-arranger with a fair number of entry-level instruments and styles. Might be a fun keyboard for adults on the go, too.
The A50 might be for teenagers. Yamaha has posted Youtube videos demonstrating arpeggio-based song creation, mainly popular musical genres. The arps look familiar - maybe from the old MM synth series? There are 138 built-in arps.
All of them are inexpensive and use the same keybed as Reface. Oddly, the F30 is better spec'ed for instruments than the A50. Probably to aupport the styles.
Take care -- pj