Picked this up for a good price at the same time as the hemlock, this might take a lot more thought ! So I shall just take my time. It had no label saying what exactly it was but I thought I would take a gamble.
I think you would need more detailed photos to verify, but at first glance it does look like an Azalea
I use 100% Kanuma soil on my azalea and they are doing well.
I would repot in Kanuma in the spring.
I have found they break rather then bend so a plastic or mica pot that you can drill for guy wires may be beneficial in the long run.
It definitely looks like a Azalea or a Rhododendron but I am not a expert.
You could wait until spring to verify flowers and then repot the following year in Kanuma.
I have 6 azaleas of different types, all garden center or box store purchases not Satsuki Azaleas, but they do well in Kanuma because they prefer a acidic soil.
I have heard some people go 50/50 with pumice but Satsuki are usually planted in 100% kanuma so I just went ahead and did it and have had good results with it.
Best of luck!