Put the half-open connections back down. There's absolutely no reason to increase it. And no, your settings are not right for xx/192 Limit: 17 Global max: 50 Per-Torrent max: 30 Upload slots: 3 In queueing set 1 download and 2 active.
changing the filenames internally within a torrent changes its infohash. That is NOT where you're supposed to re-target files if you have changed their filenames on your system
And what happens to future upgrades? Oh yeah that's right. Because you didn't troubleshoot, the problem IS STILL THERE. Downgrading doesn't solve the problem. It just hides it.
Because you completely ruined the torrent by trying to remove files from it. If you're removing files from or adding files to a torrent, you have absolutely no choice except to re-make the torrent.
You want what kind of feature? Sequential downloading? Expect it sometime after our sun goes nova. First and last piece of a file? Expect it a few months ago.