First, and most importantly, DO NOT LET THESE MAGNETS GET ANYWHERE NEAR EACH OTHER!
Forget about the levitating magnet sliding off the side. What will happen is that the neodymium magnet will immediately flip over and attract to the electromagnet with an incredibly violent force. This will either crush your hand if you are using it to position the neodymium magnet, or the impact of the magnet and electromagnet will create high velocity shrapnel that will injure anyone nearby.
Seriously, I've seen two of these neodymium magnets attract each other and slam together when they were placed on opposite ends of a work bench more than 150 cm apart. With these magnets, you will be putting a force that can lift kilograms on a projectile weighing grams.
The "25 kg holding force" probably refers to the mass of iron that the electromagnet can lift, not to any magnet-to-magnet force. The actual force between two magnets depends on the detailed designs of each. It's impossible to say without complex field simulators.