Is it easier to make a Fender Stratocaster sounds like a Les Paul or a Les Paul to sound like a Fender Stratocaster?

If you can coil-split the Les Paul humbuckers then you can make an approximation of a strat sound but you can't make a single coil sound like a humbucker unless you physically swap the pickup for a single coil sized humbucker.

One of each please! Really though as said above you can mod any axe to sound different and my AR2000 for example can mimic both quite well fooling probably most on blind A-B listening. But LPs mostly lack trems where most Strats have them. No knob or switch can change that.

You can buy a single sized humbucker or an H-S-S pickguard for a Strat to get more of a LP sound... It would be harder to get a good glassy or sparkly Strat sound out of an LP, even splitting the humbucker. My ME80 effects processor has a "Hum to Single" and "Single to Hum" setting on the front end that is supposed to do the same thing. It gets close, but not quite the real thing. It's more fun to have a selection of cool guitars to play and admire... ;-)

Thanks guys for the help!

Also is it easier to make a bright sounding pickup sound like a dark sounding pickup?

You will find it much easier to squeeze an electric sound out of an acoustic, than the other way around. If the acoustic sports a pickup already, such as a piezo, running it through a multi-effects pedal can get you all kinds of electric effects. If it has no piezo, adding a magnetic pickup is best. If you fine-tune this sound to your liking, you may even reach the point where the listener might not be able to tell you are playing an acoustic without seeing it, though feedback looms as an issue you may have to resolve.