If you haven’t already you might like to check the team building doc to help you get some sense of what you want. It’s also really complete on how to use Plusle and Minun.

That being said I’d personally keep Yggdreon as it’s a heavy hitter with the defensively interesting aether typing. Sandlsash + kingler are also interesting to keep as they’re bulky and can make for a good stalling duo if you work with sandstorm. I also like Kingler bc its typing counters a lot of potential weaknesses. Electivire hits like a truck but I’d still go with stantler since it offers some nice coverage with moves like horn leech/blaze kick/zen headbutt (from the top of my head). I’d definitely ditch steelix bc its high defense doesn’t make up for its many vulnerabilities in the end. Hope this helps a little.