Just now saw you question about Skitty. If you wanted to battle over Wifi then you would need to consider Ev training it and its Ivs but just for in game battles and completing the game you don't need to worry about all that leveling it up will be fine.
Yeah I would go on route 42 and catch one. It would probably be easier than training a mareep from a low level. Although you would probably have to train Flaafy a little bit too because it appears at levels 15-17, but thats better than a very low level Mareep.
Since Delcatty isn't available in the wild, you'll have to first get a shiny Skitty. The fastest way would probably be through breeding in the 5th gen with two parents from different language games - for example, an English Skitty/Delcatty and a Japanese Ditto, or vice-versa. The egg will have a 1/1366 chance of being a shiny!
Alternatively, you could look in the wild for Skitty in Route 116 in RSE or wait for a DPPt swarm on Route 222. Encountering wild Pokemon is much faster than hatching eggs, but the chances of finding a shiny are much lower (1/8192), and Skitty only appears about 2% of the time on Route 116.
Good luck and I hope you get your shiny Delcatty soon! :cer_smile: