There is no perfect team, so trying to put together the most efficient team ever is a waste of time. I would say pick your favorites that have the most versatility, optimize them with ev training and such, and call it a day. The rest can always be called in if you need an edge. No need to get rid of them.
Your best bet, in my opinion, would be swampert, clefable, arcanine and one of the eeveelutions. I would also for sure put in magnezone if your looking for versatility, but your not much for that so its up to you. You could just keep the ampharos in that case That last one would be either gengar, swalot, or crobat. You couldn't go wrong in the upcoming episode with a poison type as a fairy gym is very possible.
You for sure don't want to get rid of pokemon with a mega-evolution, eg, mawile or gengar. I don't believe mega evolutions are coming in e16, but it would be a huge waste to throw them out now, and they would definitely give you an edge down the line.