Holding back evolution is useful only to teach your pokemon a move the evolution doesn't learn or learns too late for your needs, it doesn't affect stats.
Second, I won't say stats total doesn't matter, but you shouldn't take only that into consideration. For instance if you look at competitive battles, a little Azumarill with 420 BS is far more useful than a legendary Regice (600 BS) no one uses thanks to his ability, moveset, typing. Reborn isn't competitive play, but you should also look at your pokemon's abilities and movesets (since Reborn gives only a few TMs, your pokemons better learn good moves naturally)
Third, your team seems rather unbalanced. Two grass types, 3 poison types. It could be interesting to have more diversity. If you're going to your third badge, I assume you're around Jasper/Beryl wards ? Do the police sidequest (finding missing officers) and you'll get a Growlithe + a mystery egg (random pokemon among 18 possibilities, all of them good ones).
Last, I guess your Noibat isn't evolved yet, it's around lvl 25-30 ? Small advice from someone who also trained a Noibat from lvl 3 in his first run: don't bother with it. Noivern is great, but Noibat is a real pain to train to get Noivern. Later you'll be able to catch Noibats around lvl 40, catching one of these is much more practical if you want a Noivern.
Hope I helped. Reborn isn't easy like main games, but it's not too hard. You would probably struggle sometimes with your current team, but it should still be possible to reach the end of the current episode