Hey there, welcome! I like your concept, it’s got a nice big wide wedge on the front and bonus points for it already having a cute little face.
I’ve never really used Fusion so I can’t help with specific CAD advice, but:
What materials would be best?
Most people are printing their antweights from TPU and PLA. Regular PLA is a bit brittle, but there’s PLA+ and PLA-ST filaments which are much tougher. MarkR wrote a good post on it recently: PLA, good or bad?
You can also get 1mm polycarbonate sheet and cut it with hefty scissors and poke holes with a sharp screwdriver if you need to improvise some little armour panels or a top plate.
Should i make wheels or buy them
Buying is definitely easier, but buying tyres and designing your own wheel hubs isn’t hard. I like lego tyres (mostly because they’re cheap and look cool, traction is pretty mid) but there’s a lot of options out there - I’ve seen people use O-rings. I would avoid playing with casting polyurethane or silicone resins until you’re absolutely sure you need to, the goop gets everywhere and the chemicals are nasty.
How could i make the flipper mechanism
It kind of depends how you want to package the rest of the robot, I recommend looking at some other robots to get some ideas. You have a lot of options, but attaching the arm directly to the servo is the easiest. A couple of holes in the flipper arm to line up with the horn that comes with the servo will give you a working weapon without much hassle.
And where could i find the high speed servo as its currently not in stock at the bbb shop
Since it’s a standard mini servo you could buy something else to prototype with and wait for it to come back in stock. I use MG90 servos from ebay, they’re not too expensive and it’s good to have a few spares around.
Hope to see it in action soon!