The problem with replacing a fork, is to find one with similar tire clearance, brake type, steer tube diameter and length, and also, geometry, as indicated in this example from wiki:

For example, that EZSport has very "laid back/slack" steering tube angle, which may have a corresponding offset/rake that will not work well with the more upright head tube angle on the minivelo. This all effects "trail/caster", which governs steering stability at speed, and wheel-flop when stopped. Plus the minivelos have really long head tubes, so you need a long fork steer tube, and hopefully you are using an aheadset setup so you don't need a threaded steer tube, but can just hack it off to the length you need and deburr the edge.

If you've got a Mercier Nano, try calling Bikes Direct, ask about a fork.