Flow rate for a small garden waterfall
Teach your baby daughter to swim as soon as possible - there's plenty of water to fall into that is not in your garden.

A pump rated for 0.7m head should be fine with a 0.6m lift.

If you cannot find a pump with  lower minimum flow (though, to be honest, you may find the "waterfall" aspect of 100 l/hr or 1.6 l/minute a bit more like a dull trickle) you can place a pipe from the pump output to the pump input, with a valve that you can adjust so that the actual water pumped out is, say, 100l/hr while the pump is pumping 400l/hr, but 300 of that is recirculating in the pipe.

I suspect the pump rate advisory is intended for a minimum flow rate of ponds with fish, etc. in them - that does not sound like your actual situation, so 400 l/hr (or more) may be a perfectly acceptable flow rate for your application.