Agree with Musho on all this stuff. Drilling is better because it keeps chance out of the equation as far as safety is concerned. Drilled tanks are not prone to failure if they get a bubble trapped in them and ALWAYS restart after a power outage. "over the back" overflows are prone to failure if they get bubbles trapped in their tubes, and sometimes do not start properly after a power outage, especially if they aren't designed right. When I was new to the hobby I went through the same thought processes you are. Scared of drilling and ruining the tank, figured why not try an over the back overflow. Ignored all the advice the experienced members gave out of fear. The thing was a pain to keep running, I had to constantly check its siphon and tweak with it. Ugh. Gave in to my fears and drilled my second (current) tank and man was I dense for not listening to the advice on how easy drilling was and how much better it is. You'll be happier if you trust us, I swear
Then, lighting. That fixture will work, but as musho says, can't be put into a canopy. If you're gonna use a canopy, a retrofit kit is MUCH better. Its really not that hard to setup. If you can handle wood screws a drill and wire nuts, you can do it