Hi and welcome
Firstly your setup sounds great for 5-6 zebras!!
Secondly, $90/fish is absolutely nothing for these fish these days. At that price I would get as many as I could. Over in the UK they are going for $300+ of your Canadian dollars!!
Zebras are relatively hardy fish but to make them feel at home you will need plenty of hiding places. Keep the temp. at around 28C and give them lots of current and oxygenation.
If you want to breed them you will need to make/buy some caves (of a specific size that you can find on here if you do a search), plenty of patience and a fair bit of luck.
You sound like you are on the right track. I would personally recommend using either no substrate at all, or a very thin layer of gravel if you are not going to have an undergravel filter.
In terms of filteration I always have two or three types on any tank. That way if one needs a clean the other will provide some form of back up.
Cheers