Two questions about an indoor dwarf cavendish
I have an indoor (Outdoor climate is not even remotely suitable for growing a banana tree here! 5a/5b hardiness with lots of precipitation and very snowy winters) dwarf cavendish that is I'd guess somewhere between 3 and 4 feet tall, planted in a large container maybe 18-24 inches in diameter. I'm new to taking care of this tree, so I have two questions.
1) The tree has two pups, one of which is growing quite quickly. For the health of the pup and the mother, as well as for ornamental reasons, I'd like to separate the two. The pup in question is maybe 6-9 inches tall at this point but unfortunately has literally only 1-2 inches of clearance next to the mother. I have never in my life transplanted a baby tree (I've done propagation from cuttings and repotting existing plants, naturally, just never transplanting a baby).
I found a helpful guide for separating the pups, but it seems geared towards outdoors and suggests using a shovel and a sledgehammer, which I'm certain is overkill for this process. Any tips for transplanting a baby indoors with these space constraints? The outdoor guide suggests that I should sever any connection between the child and bother, but otherwise doesn't appear to go too deep in the soil, and says I shouldn't worry too much about the quantity of roots I'm able to take.
2) Something about the recent growth of the mother tree has bothered me. There are two visible new leaves growing out of the top of the tree, like previous growth. They have a light green colour and are growing at about the speed I'd expect. So far, so good. My problem is that near the base of those leaves (on the inside of the tree; is the proper term here "pseudostem"?), there's a wet, slimy, black coating almost like mulch in consistency. It reminds me of the feel of autumn leaves that have not been raked.
The existing leaves are not discoloured in any other way (some mild yellowing around the edges of a few leaves, but nothing that suggests I'm in any way mistreating the tree) and there's no signs of bugs or disease otherwise.
One thing I'm doing that I think might cause this and that I have no idea if I should be doing is that I'm misting the leaves fairly frequently. I suspect that water from the misting could be trapped inside of the tree and "mulching" leaf growth as opposed to evaporating. I removed all the wet black stuff that I could without otherwise harming or pruning the leaves. Even without knowing the cause, it was obviously not something that was healthy, so removing it seemed like the best idea.
From everything I've read, I'm providing decent although not 100% ideal sunlight (south-facing window with open curtains although the climate here is naturally quite foggy and I haven't invested in any grow lights yet), watering correctly. I am periodically using a balanced fertilizer.
Can anyone confirm my diagnosis that my overzealous misting is the cause? Should I mist the tree at all?
Thanks in advance for help with both questions!