Is it ok for me to have both Gardevoir and Delta Gardevoir on my team?

With the stats it would be possible to use the normal gardevoir in a more supporty role and delta offensively if you want a more balanced team. If you use them both for all out attacking things will be hard

I use them both with Calm Mind + 3 Attacks (BoltBeam + Moonblast for D Gardevoir, Psychic, Psyshock and Moonblast for Gardevoir)