There’s so much choice now compared to when I was buying a 20″ 5 years ago (Isla bike as that was the only really good option then).
The Isla bikes have become even more refined with great attention to detail, but the Frogs are catching up. See a lot of Frogs at races now when it used ot be just Islabikes. You get a slightly lighter and slightly more refined bike with the Isla, with better resale value, but the differences are small now.
Those Orbeas look good too, but I really love that Commencal Ramone – if you don’t think you need gears (which is going to depend a lot on the child and where/how they’re riding) then that looks great. I’m a big fan of the tyres specced on that – 2.1 small block 8s – just put one of those on the front of our Beinn20 and it’s made a massive difference to riding over rougher stuff