What about using Select Output 8 if you only want one at the time and have max. 8 (can't wait for more inputs/outputs then 8 on those nodes) and connect all the filters to a Select latest 8 ? Then only 1 will be processed.
And for the others questions, Generally, for most nodes you only need a Fire on start.
But for the nodes that must move or use time inputs you need time or screen refresh frequency of course.
I guess you probably wonder when yo use Fire On Start or Fire Periodically because right now when you LIVECODE the node does not reload itself when you change a parameter (as QC does because it has PULL and Vuo right now only PUSH). But that is changing it the next update and nodes will auto reload. If already you want to see changes automatically when you live code you'll have to relaunch the node after changes (cmd-click ont a port for example) or you use a Fire Periodically but be sure to disconnect it when you're done live coding because that will slow down your composition.
Fire Periodically is still useful if you want your text strings to change every minute for example ;)
Check the manual or some examples that's in there.
And if the string has a video url in it yes you can play it. Click on the Play Movie node in the node gallery below in the node info there are links to some compositions that use that node.
However I'm not sure if Vuo can already download and play videos from the web, images yes, videos the only time I tried it did not work but that really can be because of me doing it wrong.
If even the image was stretched during the tube processing, I thought about adding the image later, with change shaders, but that will perhaps make the shader appear later. I thought it would have shaded the top and bottom as well but with a thickness of 0 it seems not (or it's invisible).
What I still wonder, there may be some info about about that that I have missed on the website but if I create a very detailed tube with > 100 lines and apply a live image to it, is it better to reshade the tube lower in the node pipeline with some Change All Shaders or can I apply it directly on the tube node and only the shader part of the node is being recreated (and not the whole tube).