I suppose I'd suggest considering a different kind of filter. I know some people use them and are successful, but most seem to go either HOB, or something like this in tank canister
made for nano set ups
For the most part, air stones are not very popular in planted tanks, and that's pretty much what one of those sponge filters is. Most people are using either a small powerhead or just using the filter output (either HOB or canister) to agitate the surface and promote good gas exchange.
I think you'd find that a HOB refugium will not be necessary for increased biofiltration. You will likely have plenty regardless of what filter type you use. additionally you'll have beneficial bacteria colonizing on any rock surface or sand, etc.
I'm not familiar with the substrate you listed, however, I'd still suggest using aquasoil. Substrate is incredibly important, and aquasoil is an industry standard. In my tank, which is 1.5 yrs old (yes it does matter a year down the road), I have only added 2 root tabs...which weren't even necessary, I just did it under two plants that are said to be heavy "root feeders" if that's even a thing. Aquasoil will not only provide nutrients to your plants, it will help buffer your pH down to a slightly acidic range as is ideal in a planted tank. Additionally, it will help cycle your tank by feeding your growing BB colony with ammonia.
There's no reason you can't start with liquid fertilizer right away, however, its very important to find that balance between light/fertilizer/carbon. So, if you're not using CO2, it may be very easy to over fertilize (and over light) which will just make your tank an algae farm. Also, without CO2, you might have trouble getting something to carpet well.
In order for your plants to thrive, you NEED all of these things in check:
You can add plants while your tank is still cycling. DSM is great...but probably not for beginners?
for what its worth, I don't think the wood is too big for the tank...IMO you tend to need quite a bit more hardscape than you think at first.