Yes, seeing as this is only what we can see on a DS screen, it is possible the same character is farther down where we cannot see him. If this is so, then Mareep may still be catchable after the first gym like in the originals. Whichever way it may be, it is not a huge big deal to me. The first gym leader is not extremely hard to defeat like you have stated and catching a super effective type for Folkner will only decrease the level of difficulty from the start of the game. Nevertheless, I'd still hope to see some repositioning of the Pokémon to appear in certain different locations from the original, but we'll see how far of an extent this idea maybe taken, if at all.