Yes it looks like you are seeding. Seeding does not necessarily mean you are uploading, it just means you are available to upload.
That torrent has 15 seeds and shows 1 peer and that would be why no upload (the peer may not even be a real peer)
If this is from a private torrent site, check there. It should show you as seeding on this.
I checked under "General." It is not marked as a Private Torrent. I got it from TPB.
It looks like there are 4 different trackers though. I know trackers log if someone contributes at least as much as take, but does seeding via Vuze register with the trackers? It seems confusing to me. What if each tracker was from sharing the torrent on different sources (i.e. not TPB)?
Does having an adequate share ratio mean I must seed the file longer/more since there are 4 trackers?
Public trackers do not keep track of ratio. Only private trackers keep track.
It does not matter how many trackers there are. The ratio you see for the individual torrent is what matters and you are the only one who sees it.
Keeping a good ratio on public torrent sites is just a personal choice.
You got the content because someone else stayed to seed, so just putting back in.
On a torrent like that, personally I would keep it open for a few days and if no action I would have no issue deleting it.
Keeping it active for longer will not have any negative effect on download (nor will it have any positive effect on other downloads)