Hi Gumbanomicon,
there is no limit for the lanes or depths. You should be able to reach offscreen nodes using arrow keys or the scrollwheel on the mouse.
There is no real text limit, but the text is show in normal width and will automatically wrap around if the edge is reached. This leads to a few instances where the texts might overlap. You can adjust the font size in the plugin parameters (see Font Settings).
Check if the Bone Mail Skill ID is correctly set in the tree.
In your second picture the head seems kinda full. You can change the amount of trees visible in the plugin parameters (see Header Settings -> Header Columns)
There node shows the description defined in the tree. It then shows a list of the skills you unlock together with the descriptions. This is mostly done so you can put more flavour into the nodes or can be used for nodes that don't actually unlock skills. (Nodes can also change switches or run common events on activation).
I'm happy that you like the plugin. If you have any more questions, feel free to ask them
Best regards,
Felski