Hi and welcome to the forum.
There are some great articles to read up if your new to the hobby, and you seem to be doing things right so far, which is more than can be said for some. Fishless cycling is the way to go to mature your system and get it ready to sustain life, so keep doing that and don't cut corners.
As for your stocking ideas your on the right track in terms of adding fish week by week and not all at once, which is good. However, your stocking ideally needs to be tweaked a little. Its fine what you plan on having in the tank, just in larger quantities. If it were me i would stick with a 'shoaling' fish, your oto's and then maybe either a small centre piece fish, such as a dwarf gourami or get some Japonica/Amano shrimp perhaps. The quantities of fish you've listed arent ideal. Tetras, guppys, danios and plattys are all active group fish, which naturally like the company of their own species. So selecting your favourite and having a group of 7+ of them is going to be far better. Also i'm a firm believer of the "less is more" motto. I prefere an active group of one fish, to a random miss mash of several species all swimming on their own. Make sense?
In a 40L tank like yours, i'd be inclined to stock it as follows;
2-3 _ Oto's
7 _ Bloodfin Tetra
4 _ Yellow Honey Gourami 1m/3f
That is how i would set the tank up personally. In terms of decor, i would add a small piece of wood that is quite tall with a few branch like extentions. I would place a couple of smaller rocks around this. For plants i would start of with 'easy' plants that don't require too much looking after. So i would add Anubias barteri var nana to the lower section of wood, this plant likes to be tied down to the wood, making sure the rhyzome of the plant is never covered (else it rots). Higher up on the wood i would also tie on some Java Fern. In the substrate around the rocks i would go for Cryptocoryne species such as C Wedntii (green & brown).
Hope this helps,
James
10 _ Amano/Japonica Shrimp