Unfortunately, It is a rare plant retailer who can offer reliable advice on plant care.
The best pot for most any plant you acquire is the one it is grown in by the nursery. As soon as you start to disturb the roots by repotting or changing the soil you start to create problems unnecessarily. You can set the plastic nursery pot into something more attractive but don't repot.
Skip the fertilizer altogether.
Make sure you have a good match between the available light and the light requirements of that particular plant species. If you don't have a good light match then nothing else you do will matter.
