Ok, fair assesment. I too, prefer to have Pokemon of mixed elements on my team, for coverage. However, the next 'Special Event' Pokemon to be introduced is Zoroark, who will be Dark/Posion type. As for Gardevoir, I thought long and hard what typing I would give her to replace Fairy, and Normal seem to be the best fit.
You are correct, Lopunny does cover the Normal typing, but since Gardevoir is primarily SP. Atk based, she can be your counterpart on the opposite side of the spectrum.
Either way, there will be much more than 6 Waifumons with augmented stats, and each one can be a good fit for your team depending on your playstyle/build. Ultimately, you have to swap some of your waifus out and change them around.
Hope you find this answer satisfying. Best regards.