The team I have in mind right now is:
D. Blastoise
Gengar
Rotom-wash
Lapras
D. Raichu/Togekiss (Don’t know which one yet)
A ground-steel type (Maybe bastiodon, because I just picked that fossil)
Any tips, or recommended changes Is should make ?
I maybe want to switch Lapras for D. Gardevoir or Gallade, but then I do have a second ground weakness. And I’m hesitating between D. Raichu and Togekiss because I kind of want another delta on my team but I think Togekiss is a lostronger than D. Raichu.
Would probably depend on your difficulty setting. If you’re on normal you could probably get away with using ones you like.
Hard requires certain measures, with not much room for aesthetics.
Biggest thing I’d say is just be ready to swap pokemon out often. Absolutely no reason to try and stick with one core team, especially because very often you can get good additional options much later on, and catching old pokemon back up to the new level cap/range isn’t that hard.
As far as actual teams go, I’d say look into Steelix as your Ground Steel type. He’s a flex pick with his mega stone you can access first (Steelixite - Fire), and gives you some nice type coverage options with the fact you can mega-evo into Fire/Steel with the ability Foundry, and gives you Stealth Rock access, which can be quite helpful in the early to mid game, and breaking Focus Bands is quite important for plenty of later fights.
I’d personally drop Lapras, and swap them for Delta Snorlax. D-Snorlax functions as a wonderful sweeper with Belly Drum, an exceptionally durable wall with Drain Punch and Ingrain (Especially if you Belly Drum before starting to Drain Punch away), and overall is just a very solid choice. You don’t get much type coverage from him, but he’ll just use sheer bulk to be useful, and his Thick Fat ability basically drops him down to only having 3 type weaknesses, Flying, Bug, and Poison.
Another pokemon I heavily recommend is Tyranitar. Honestly one of the strongest pokemon you can add to your team with his Armor item basically rendering him as having more than legendary stats, and Sandstream means his Spec-Def gets even more insane, without taking up a mega-evo slot in a team.