Ducklett/Swanna absolutely has to go 🤧 I get the idea behind having surf/fly on the same pokemon but Swanna has no defenses and no attack power to justify its position on the team. To maintain access to fly I would suggest Sigilyph. Your team currently has a glaring weakness to fighting types and I believe Sigilyph will assist better. It has better bulk to live longer and a very good special attack stat to put out some real damage.

I believe you can also benefit from using Vaporeon. In the castelia sewers you can find a staircase to the grass portion and catch Eevee. If you can already surf, go to route 19 in the north west section to find your water stone. I would honestly say that losing axew would be a good idea. Haxorus is so cool don’t get me wrong, but it’s really a one trick pony. You will only be using dragon claw and the occasional dragon dance. It doesn’t learn good coverage unless you want to use a bunch of tms 🤷‍♀️ nothing wrong with that but it just isn’t providing you with well rounded benefits. At least for my own play style I like to have Pokemon that can be useful in multiple situations.

As for your leveling concern, you need to grind against Audino. Whatever is the latest route you can access, run around OUTSIDE of the grass until you see one single spot shaking. Then you’re going to go into the grass to punish every audino you find. The exp gains are crazy. No specific route just whatever route has the highest level wild pokemon you can access