I refrained from posting here earlier, because well, you probably didn't want to hear this, but eh wells.
In general, fish will take time to switch from one food to another. They can be picky, and this can take up to weeks of starvation.
However!
In this case in particular, there is a worry that they may never switch. Why? Eartheaters are exactly that, eaters of the earth. They are bottom feeders, and whilst you CAN get them to accept floating pellets (heck, I had a pleco that went to the surface to eat once), but the problem here is if there's food at the bottom, especially if you have sand or gravel, they'll never ever think of ever going to the surface. They'll stick to the bottom and manage to scrape by with scraps from there, but will slowly be starving and dying. By the time they realize that they need a different food source, it might be too late and they're just too weak to care.
But! On the other hand, a few of your tapajos have found their food, which is good. Cichlids do learn from each other (I've had fish that never eat pellets, and then I toss one in that went for it, and suddenly the entire tank start eating pellets), so given that, the other tapajos could eventually learn to follow the lead.
So yes, in the end, in this case in particular, it's gonna depend on a lot of factors as listed above, and it's up to you if you want to take the risk. Perhaps just try your best, but purchase a small bottle or whatever of sinking pellets just in case they can't get used to floating pellets in time.