Welcome!
It's like you're reading my mind! I've had a project like that in mind for some time, but I lack your mad skills.
Since you're going for a period correct look, I'd forget about the filter and just route the vent hose behind the engine, and point it at the ground.
Do you plan to run a battery? If not, you might be able to fabricate a block-off plate and remove the starter.
Did you fabricate the frame? Where did you source the rims and tires? Please share some more details about this terrific build.
