I'm using icons to categorize my folders but sometimes I move the icons to a more appropiate place so the next time I load the folder, the folder icon isn't set. Could I edit manually (replace text) the folder configuration to avoid searching its icon again? Where are those files? Could I edit also view mode for a certain folder manually (changing a value inside a file)?
Caja stores the info you're looking for in GVFS databases.
You should be able to make changes like you describe using the gio utility which can be used to view, edit, or otherwise manipulate the data in the GVFS databases. See man gio.
The particular gio commands that will likely be of most interest to you initially are info (shows information about the given locations) and set (sets a file attribute on a file).
The gio utility apparently replaces a collection of older GVFS commands such as gvfs-info (as suggested at, e.g., https://unix.stackexchange.com/a/200666/274746).
As for the location of those files, the database files should be in
$XDG_DATA_HOME has been changed. In the latter case they should be in
$XDG_DATA_HOME/gvfs-metadata. See https://stackoverflow.com/a/10964074/8100489. Either way, you'll most likely find it difficult or impossible to edit them directly (as suggested, e.g., at https://askubuntu.com/a/47548).