There are many people who submit outland applications before two years of marriage. Follow the instructions for the additional relationship proofs. Presumably you’ve been living together since marriage? Did you generally follow the customs of your culture/religion for dating/engagement/marriage...
What sort of ties does he have to Cuba (family, property, job etc)? Has he had other visitor visas to other countries before? I’m far from an expert on TRVs but my understanding is that they look at things like that. You may want to research if it’s better to apply for a TRV before or after...
Plugging in the info you provided on this gave me that you are probably not. https://ircc.qualtrics.com/jfe/form/SV_3pJ5oXgZNBj0r1c?Q_Language=EN
I think your dad may have a very small shot at it, but that would be highly dependent on him having all documents about his grandmother’s citizenship...
I don’t think you can submit an application for your deceased grandfather, so I think while you’re right in theory about the descent, because your grandfather never got his Canadian citizenship recognized while he was living, you are out of luck.