Since I'm not a huge expert, I'll only give advice on Pokemon I have used in my playthroughs:
- The Delphox looks good. Perfect moveset. If you want, I guess you could let it have Sunny Day - and change Heliolisk's ability to Solar Power, to create that synergy effect
- Eerie Impulse on Heliolisk could be replaced with an attacking move that offers more coverage. Currently, I think Dark Pulse and Grass Knot are good options. Thunder Wave could be replaced with Glare - so that it will be able to paralyze Ground types. Again, Solar Power would be an option to consider
- Since we already defeated Radomus and Shade, I think Shadow Ball can go away now for Noivern. Flamethrower is a much better option.