Filter's only really worry about removing waste from your tank, nothing really to do with plants. They are also the prime place for holding your Beneficial Bacteria or BB. When cycling a tank, that's what you're growing is BB which converts ammonia to nitrite and nitrite to nitrates which are then taken out of the water by a water change.
Now if you were to get MANY plants and stuff them into your little tanks then you'd be doing something called a Silent Cycle. Basically the plants act as a buffer between the harmful levels of ammonia, nitrite and nitrate to protect your fish. If you had lots of plants, you could immediately put your boy in the tank and he'd be fine! You still have to do at least a weekly water change but you wouldn't have to worry about levels of ammonia poisoning your fish.
As far as substrate, it doesn't matter. What your doing then is just having a regular Planted Tank in which you would use fertilizers each week to feed your plants. I suggest having a Liquid Fertilizer like API's LeafZone or SeaChem's Flourish and actually cut the dosage in half and dose twice a week instead of once a week like the directions usually call for. This will give your plants two small meals in a week instead of one big one, I'd like the small meals too haha
You can also get something called Root Tabs, these are slow dissolving tabs that fertilize your plants over a period of about 3 months. You can break them up so you don't have to use a full one and you can spread them over your tank instead of just one place. You push them under the gravel/sand and you're set for about 2.5-3 months! I usually put them under plants so that I don't vacuum them up when I do my weekly water change.
Now you can still use sand and it would be considered a Planted tank because there are no nutrients in the sand that are feeding your tanks. There's another thing called Natural Planted Tank or NPT. That's when you have a layer of soil underneath your layer of sand. The soil then feeds the plants as it would in the wilderness and you wouldn't have to dose fertilizer all the time.
But either way is effective. All my tanks are just regular Planted tanks and they grow just fine in sand/gravel! I use API's LeafZone twice a week at the half dosage and that's pretty much it! I haven't used root tabs in a while because I ran out so i'll be getting more soon
Hope this helps!