Hi!
No, i would not advise you to do an undergrad program because you will risk getting your application rejected.
Well actually, a 1 year program can give you a 1 year PGWP kaya lang 1 year is just too short to get your PR.
What you can do is get two postgrad programs back to back. Ok ra man na and they will still give you your 3 year PGWP. Abi nako from reading diri Dili pwede, pero sayop sila. Pwede diay. Kaya Lang hassle gamay kay you need to renew your student permit after one year. But it's totally fine to do so.
Unless you want to try another province instead of Montreal