The level of top end raw talent isn't really in question. Indeed, top NCAA programs do typically have a few guys that are more talented than a regular CFLer, or even a star CFLer. The issue is that football is played 11 vs 11, or 12 vs 12 under Canadian rules. After those first few high NFL draft picks, the vastly superior depth of the CFL team is going to be the overriding factor. Even a program like Alabama that is practically a factory of pro football players is only getting a few guys per graduating class drafted to the NFL in most years. So there's still going to be several guys on the field that aren't pro-caliber, and they would be exploited badly by a team made up of 100% pro caliber players. Especially since most of those are seasoned veterans.
A strategy against Alabama would be pretty straightforward. Don't throw at Minkah Fitzpatrick, who would certainly be the best safety in the CFL. But a QB like Mike Reilly or Bo-Levi Mitchell would pick apart the rest of the secondary with ease. They'd face some pressure from Alabama's beastly linemen, but they get the ball way much quicker than a typical SEC QB, so that would be mitigated. Jalen Hurts couldn't move the ball against Georgia's defense, who had two guys drafted. I honestly doubt he would score a point against a CFL defense. Alabama could probably pick up some first downs by running the ball behind their behemoth offensive line, but it wouldn't take long for the CFL team to just stack the box and make them throw. Calvin Ridley is the only credible threat through the air so he'd get doubled, and I doubt any other Alabama receivers could get open enough against pro defensive backs for a Hurts-caliber QB to complete passes with any regularity.
No, but it would certainly take a team that consisted almost entirely of future pros, and a majority of them seniors.
Being physically advanced might help, but those thousands of extra reps and countless extra hours being coached up and taught to read plays run by much more complex pro offenses and defenses is going to give the pro player a huge advantage.