I've tested the eyepieces of the kit, and they're not good value. I would go for fewer but better eyepieces. A Celestron 32mm omni for wide views (due to a wider apparent field of view, you will get wider views than when using the 40mm one). For higher magnifications (ie: shorter focal lengths of the eypieces for the same telescope), lots of experienced people suggest getting the "gold-line" eyepieces as a starting point, sometimes branded as svbony. They are supposed to have a very decent quality for the price you pay if you choose the shorter focal length ones and use them in a long focal ratio telescope, like the 6SE and other Cassegrains (f/10). See for example the 10mm and 4 mm ones. They have longer eye relief than the short focal length eyepieces of the kit (meaning that they don't requiere you to put your eye too close to the eyepiece), and they have a wide field of view (so you don't feel like you're looking through a straw). The wider versions (20,30-ish mm) of the gold-lines seem to be not that good. They suggest to look for ghosting (diffuse internal reflections) and as for a replacement if needed. You can research that aspect if you will. Another good option seems to be the Agena Starguider Dual ED series, also better in slower (higher focal ratio) telescopes, with good field of view and eye relief. It seems they are not available in Amazon Canada, but check this in the US store.
Although using eyepieces by themselves will get you better quality, a decent enough barlow is a good idea to get more magnification if needed. The celestron omni 2x barlow is good enough for a start.
Now you have 30 CAD still available if you had bought the kit. Maybe get a moon filter. Not sure if this is good enough. Note: the so called "skyglow and moon filter" is to partially diminish the natural night glow of the atmosphere, and the atmospheric glow due to the moon, and work better in darker skies.
I recently bought a C6 optical tube assembly (OTA), basically the same as the 6SE. I have not received it yet but as for eyepieces I got the celestron omni 32 mm, I'll be testing the stock 25mm Plossl that comes with the OTA, I added a Meade series 5000 HD-60 9mm for higher magnification adn good eye relief, and the celestron 2x barlow. The latter will allow me to expand the set as if I had a 18mm (=32mm/2), 12.5mm (25mm/2) and 4.5mm (9mm/2), which don't overlap my actual set, while keeping relatively wide fields of view and good eye relief, but with a small penalty for the extra glass in the optical path.
Also, note that the magnification you will get will be limited in reality by the stability of the atmosphere of the moment and place you are observing from. For planetary and lunar observation you will probably want to magnify as much as you can. The 6SE is capable in theory of getting usable magnifications a bit above 300x. But getting 300x magnifications will probably be feasible only a few nights when the atmosphere is stable. You get that with a 5mm eyepiece in the 6SE, which has a 1500mm focal length. Your magnification will equal the focal length of the telescope divided by the focal length of your eyepiece: 1500mm/5mm = 300. So you are better off with less magnification for MOST of the nights, since you will be able to use that more often. Also, when using the 6SE with the nexstar mount, you will have a bit less of stability, due to the support of just one arm and the quality of the mount and tripod. This makes observing with higher magnifications a bit more cumbersome, since any light touch, like when you are focusing, will make your object move a lot for a short while.
For astrophotography, use a T-adapter and a T-ring. The latter should match the mount of the camera you will be using; in your case it should be one for Canon cameras.
There are quite a few out there and it really depends on your budget. Here a few that I believe are good for DSOs.
https://www.amazon.ca/Celestron-Omni-1-1-32MM-Eyepiece/dp/B00008Y0SS
http://www.amazon.com/Televue-32mm-Plossl-1-25-Eyepiece/dp/B0001GO16W
I like the Celestron because it is fairly priced and it is a decent eyepiece. If your budget can fit a Televue, then go for it! Hopefully this helps.