To start with, my knowledge of Dutch nationality law is based on my own research because my circumstances are similar to yours. My circumstances are not the same as yours, though, and I am not very active in keeping my knowledge up to date, so please take this as a starting point in your own research, and not as a definitive answer to your question.
To summarize, I'm afraid that the answer does not look good for you: You may have been Dutch when you were born, but, if so, you probably lost your Dutch citizenship on 1 April 2013.
To determine definitively whether that is the case, it is critical to determine whether your paternal grandfather ever became Canadian, and, if so, when. In general, voluntarily acquiring another nationality results in the automatic loss of Dutch nationality.
Your mother's parents most likely lost their Dutch nationality when they naturalized in Canada. Since they did this before her birth, she did not have Dutch nationality at birth.
If your father's parents were married, then his mother's naturalization is unimportant, as he would only be able to inherit Dutch citizenship from his father. If his father naturalized before he was born, he would not have been Dutch at birth. Otherwise, he was Dutch at birth. If your father's parents were not married, the situation is more complicated, but in such a case he could have inherited his mother's Dutch nationality.
The rest of this assumes that your father was Dutch when he was born. If he was not, then the following is not relevant.
Under this assumption, the next question is whether your father was still Dutch when you were born. Since he was born in Canada, he did not aquire that citizenship voluntarily, so he was a dual national at birth. However, since he was born outside the kingdom, under the 1892 nationality law he lost his Dutch citizenship by residing outside the kingdom for ten years after he turned 21. He was born in 1955, so this happened in 1986, after you were born. (Or, if the ten-year period was reset when the law changed in 1985, he lost his Dutch nationality in 1995; that's still after you were born, of course.) You were probably therefore Dutch when you were born.
(I also assume that your father never had a Dutch passport or other document showing Dutch nationality; if he did, that would have reset the 10-year clock, and things get fairly complicated in that case, because of the following.)
The provision for dual citizens losing Dutch nationality based on residence outside the kingdom was tweaked a few times, starting in the 1980s. From 1985, a dual national born in the country of the other nationality would lose Dutch nationality by living for ten years in that country. The ten years began when the person turned 18. This would have applied to you when you turned 28 in 2010, except for the fact that this law was changed in 2003. You were therefore Dutch in 2003, and we need to look at the changed rule.
The 2003 rule provides that a Dutch citizen who holds another nationality and lives anywhere outside the Kingdom of the Netherlands or the EU for an uninterrupted period of ten years loses Dutch nationality. The ten year period starts on April 1, 2003, or on the 18th birthday, whichever is later. (The ten year period can be reset, however, by acquiring a passport or other nationality document such as a consular declaration of Dutch nationality.)
You turned 18 in 2000, so your ten year period started on April 1, 2003. If the assumption about your grandfather is true, and if my analysis concluding that you were Dutch on April 1, 2003 is correct, and if you never got a Dutch passport or lived in the EU or the Carribean Netherlands for a year or longer between 2003 and 2013, then I'm afraid you would have lost your Dutch nationality on April 1, 2013. (There is another exception that probably doesn't apply: marrying someone who is abroad in the service of the Dutch government or an international organization to which the Netherlands belongs, or being such a person's unmarried partner.)
Finally, there are several ways for former Dutch citizens to regain their Dutch nationality. Most of the simplified procedures appear not to apply to you, but it seems that if you can get a non-temporary residence permit in the Netherlands for one year, you can apply to regain your Dutch nationality without having to be naturalized. Follow the links below for more information.
To conclude, as you can see, this is all very complicated. If you want to be sure not to leave any stone unturned in your effort to become a Dutch citizen, you should probably do the following, and consider working with a Dutch lawyer:
- Determine if and when your paternal grandfather naturalized in Canada
- Read the law yourself to see whether there is some aspect of it that applies to you but which I might have glossed over under the assumption that it is irrelevant
- Apply to the Dutch consulate for a declaration of Dutch nationality, to get an official ruling (rather than relying on this lay analysis)
- If the Dutch authorities find that you are in fact a former Dutch citizen, investigate the options available to you to regain Dutch citizenship.
Official information about Dutch nationality and regaining lost Dutch nationality: