I’d try to get them riding without stabilisers. My boy learnt to ride in February at 3 years and 4 months. We had him riding without stabilers within minutes and he’s never looked back. I see children twice his age still stuck on stabilisers. My advice would be to get them a balance bike (Frog do a great one called the tadpole but there are lots of other). My boy starting riding a wooden balance bike at 2 and a half and took to it quite quickly. By the point he switched to the smallest size Frog bike he could go about 50 meters without putting his feet down so had great balance and moving to a real bike was easy, I just took the pedals off for a few minutes to get him used to the feel of the bigger bike. The biggest challenge was learning to use a break and not his feet which is why I think the frog (or equivalent) is a good option.
I think what made the transition so easy was that we got him a small light bike that fitted him there an then. Less than a year on it’s starting to look a bit small for him, but’s it’s given him lots of confidence. I almost bought him a first that bike he could ‘grow into’ but a friend who teaches kids and adults to ride said the most important bike was here first as if it’s too big, too heavy etc they will quickly lose interest. As a parent (who often has to carry his bike when he gets bored) I really appreciate a bike that weights 6kg and not 10kg+ (I couldn’t believe that kids starter bikes at Halfords weighed more than my own bike)! Frog and Isla bikes are the best biks around to learn on. They’re not cheap but worth it. We bought second hand and will easily sell on for the same we paid so worth the investment.
My gut feel is that a Moulton mini will be just took big for their first bike. Better to get them confident and then get him on his special bike just like his grandads when he’s a bit bigger. I certainly intend to get my boy on a Moulton when he’s ready but reckon he’s still a couple of years off and am looking forward to having him help me pick a colour and get it ready for him!
One final tip, my friend old me to ignore the tradition tip to teach you child to start by getting them to raid the pedl and push down. It’s really not intuitive when they’re small. Instead he said go for ‘scoot scoot ride’ which is essentially having one foot on the low pedal and pushing off a couple of times with the other foot to get up a bit of speed and balance.
A long old post but hopefully some useful thoughts and ideas in there!