I think "yes." But I don't think it's very cut-and-dry, so let me explain my thinking.

First, let's look at the "higher level clause" of Enhance Ability:

When you cast this spell using a slot of 3rd level or higher, you can target one additional creature for each slot level above 2nd. (PHB p.237)

Okay, we can target more creatures. So let's go back to the first lines of the spell description:

You touch a creature.... Choose one of the following effects; the target gains that effect until the spell ends. (ibid., emphasis mine)

So to my mind the higher-slot clause starts modifying the earlier spell description starting on word three. Now you're allowed to {touch a creature, choose an effect, target gains...} more than once.

For contrast, imagine if the authors had chosen to phrase the description this way: "choose an effect, touch the target and it gains that effect." If so written I think the multiple targets would all gain the previously-chosen effect. But in our world the target is chosen first and--to my thinking--that "reboots" the whole spell.