Hi! First of all you're really pretty, your eyes are gorgeous! Also apologies ahead of time if this is too late.
Moving onto makeup, you have a lot of the basics that you'll need so that's good. Some things I'd really suggest getting as well, especially to make your makeup last through a con day, is some primer, setting powder, and setting spray. NYX's Photo-Loving Primer (~$13), HD Studio finishing powder (~$10), and matte setting spray (~$8) are all ones I've used and liked. Wet n Wild also has a setting spray (~$2) that works well and their own primers and setting powders with similar price tags, but I can't personally vouch for those. I'm not sure where they sell them in Canada since I'm from Seattle, but here they're at a lot of drugstores. I'd also recommend getting a neutral eyeshadow palette if you don't already have one, and maybe some false lashes for cosplay (they're not as scary as they seem, I promise), but those aren't an essential.
As far as learning techniques goes, YouTube is your best friend. Tutorials are sooo helpful and taught me a lot. Feel free to PM me if there's anything I might be able to help you with. :-)