"-I'm using my VPN (PIA) port forwarding number. UPnP and NAT-PMP is enabled on both."
DISABLE UPnP and NAT-PMP if you're using VPN (PIA) or most any VPN or proxy. UPnP and NAT-PMP will try to port forward your local router, not the remote VPN server...causing a possible security failure for the VPN.
"-DHT, PeX and LPD is enabled on my clients, but it doesn't really matter because they're disabled on privates."
DHT and LPD are both global networks -- they run even if all your torrents are private. Either disable DHT and LPD/LSD on all your BT clients or enable them on only 1 that you're likely to download public torrents on that needs them.
"1.) Should I update to qBittorrent v4.1.4? I'm currently on: v4.1.1."
Wait a version or 2 more if you're not having major problems with v4.1.1. There's some big fixes coming through soon for libtorrent + qBitTorrent.
"2.) This has always kinda confused me a bit..." ..."a.) "Seeds" 0 (113) means there's 113 people seeding the files"
If you're seeding a torrent, you won't stay connected to other seeds except extremely briefly. (milliseconds even) So 0 should always be the first number for seeding torrents.
And no, that doesn't mean there's 113 people seeding those files. It means 113 different ip addresses were reported as being a seed for that file possibly over the last few days/weeks/months. A single computer can have multiple ip addresses (IPv4, IPv6, LAN ips inside the router, maybe a separate wifi mixed in, etc), the internet ip can change regularly, and other BitTorrent clients and trackers may be misreporting seeds and peers that never actually existed.
"b.) "Peers" 0 (1) or 2 (2). What does this mean?"
0 (1) = 0 connected peers at this precise moment out of 1 peer believed to be on that torrent sometime in the last few hours/days/weeks/etc.
2 (2) = 2 connected peers at this precise moment out of 2 peers believed to be on that torrent.
"c.) If I see Seeds 0 (4) and Peers 1 (2), does this mean that the person downloading is ONLY connected to 2 of the 4 seeds?"
The lone, connected peer out of the 2 "possible" peers may or may not be connected to the 4 "possible" seeds. Their connectivity is only indirectly communicated to your seed via PEX (Peer EXchange), which is disabled on private torrents.
"Mind sharing the problems? (Cliff notes)."
https://qbforums.shiki.hu/index.php/topic,3956.0.html EXTREME Speed Tests of various BitTorrent Apps
...and other posts I've made at this forum, especially concerning Deluge, Tixati, Transmission, uTorrent.
"Do you think this kind of sustained activity 24/7 is too much for my HDD/300/300 connect or may cause my ISP to wonder what's going on?"
That picture shows you connecting to only 0 to 2 peers on each of those torrents and no seeds. I'm guessing all those torrents are seeding. That's only going to add up to being a big deal if you have 100's or 1000's of active torrents with active peers on them. Individually, the speeds aren't even very good -- are some of the downloaders on really crappy DSL?