Wires and cables as well as connectors work the same way. They have voltage, and current, ratings which are maximum ratings. It is always OK to use less voltage or less current than the rated maximum.
The maximum voltage of a wire or insulated connector is determined by the insulation. A higher voltage means the insulation will be thicker or made of better materials. A multi-contact connector might also have larger distances between contacts to prevent arcing.
The maximum current of a wire or connector is determined by the conductor thickness and contact area — which determines the resistance, and therefore the amount of heat produced. A wire or contact which has less resistance, or can tolerate higher temperatures without being damaged, (or is in an environment with better cooling) can handle more current.
Therefore, the only consequence of using an over-rated connector is that it will be larger than necessary. If they're not too large for your application, then don't worry about it.
(Another way being too large could affect things is in the particular case of crimped joints: attempting to crimp a large crimp barrel onto a small wire will make a poor joint likely to fall apart. They should only be used for the wire sizes specified.)