Hey! I go to York, but graduated from the Professional Writing & English program.
I have a ton of friends who did all of those majors, and Law & Society definitely will have the biggest relation to law. Many of the courses offer you the chance to do mock trials, critique major SCC decisions, and discuss jurisprudence in general. If you're genuinely interested in the law it would be a great segway. Not sure which would be the 'easiest' though; I think that largely depends on what you genuinely enjoy learning about. Here are some insider tips about the programs from a York student:
York's psych program is absolutely massive, so make sure you are okay sitting in 500-700 people lectures and having large tutorial classes. Lots of people talk. It's kind of a grind. The BA is easier than the Bsc I've heard.
I don't know much about our crim program, so can't comment on that.
Poli Sci at York is great. Also very large, but not as big as psych. Some of the courses will also let you research legal topics, but it will also allow you to explore political science in general, giving you a nice combination of info related and unrelated to your future legal studies.
Hope this helps If you have any questions about York please feel free to ask! Did my BA there and am also finishing my MA there.