Welcome to the forum!
When you say "dropbox folder", do you mean that you want Inkscape to browse to the dropbox website and open a template that you saved there?
Not unless you know....I forget which language it is, but if you know the right language, and you could program Inkscape to do that, I guess it's possible.
But if you've saved the templates on dropbox, they must be SVG files, right? All you need to do is open them using Inkscape. Instead of opening Inkscape first, browse to dropbox first. Click to download the file.
If you have SVG files associated with Inkscape on all the computers, when you click to download the SVG file from dropbox, the computer will automatically suggest that you use Inkscape to open it. (At least that's how it works on Windows.) I don't know if you could double-click on the file in dropbox, and Inkscape will automatically open it. But it might.
Or you could just load whatever templates you need into Inkscape's user directory, on all of the computers. You would just need to do it once. Are they all Windows computers?
Or maybe you could carry around the templates on a little USB drive, or something like that?
