This is how long the directory and file structure stay in memory.
This depends on the remote and if the remote supports it, it's how long it polls the remote for changes/new files and that will invalidate the previous item and get a new listing.
Both of those have really nothing to do with vfs-cache-mode.
This really only comes into play if you are not using writes/full.
That is for writes/full cache modes and it's how often it checks the cache to remove files if it hits the max size.
Note that files are written back to the remote only when they are closed and if they haven't been accessed for --vfs-write-back second. If rclone is quit or dies with files that haven't been uploaded, these will be uploaded next time rclone is run with the same flags.
--attr-timeout duration Time for which file/directory attributes are cached. (default 1s)
That's how long it keeps file attributes in memory when it gets a listing of them, which is normally 1 second.
Best bet is to use defaults and if you want to change something, understand what the flag does and why you are changing it.
I can't figure out what you are really trying to get to so I wish I could be more helpful as you seem to have a random stream of questions that are all unrelated.
If you aren't sure, use the defaults and remove it.
Not sure why you are setting half the items you are setting.
Lots of details are missing like what backend you are using, what OS etc so it's hard to guess, which is why we have a help and support template that guides a user to fill out all the details up front.