1) I have read here at BTCTalk that public servers (when transmitting BTC) can read entire wallet histories, thereby lowering privacy. If I use a VPN and/or TOR, would the first public server node likely be in "my area" (if I connect my VPN to Singapore and I'm actually in Spain for example)?
2) Similarly to above, if I run another transaction later that day, is it likely that that second tx be picked up by that same public server? Or better to switch the VPN exit to Malaysia?
None of that matters. I think you're overvaluing the method by which you connect to servers, hoping that your method of connecting is helping you remain private and secure. It's not.
For example; if you are always changing your IP through Tor or VPN, but always connect to the same server, that server operator knows it's the same wallet connecting every time despite the different IP addresses. Connecting to different public SPV servers every time only distributes your transactions to more server operators, increasing the potential that someone will use the data to target you. There's no method of connecting to a public server that will guaranty your privacy.
Realistically, the only way to privately use a wallet that needs an SPV server connection is to run your own server. Electrum Personal Server is easy to use, very light, and will provide you the privacy you seek.
3) If the above does NOT help my privacy much, perhaps storing BTC quietly in various wallets (seeds + passwords) help? My issue here is that I want to be able to conveniently remember where all my BTC is without having to remember 10 wallets (w/ seeds and passwords).
That could help, but it seems like a lot of trouble. It would be much easier to just use Bitcoin Core as your main wallet, and effectively achieve the same results. Core doesn't need to connect to SPV servers, and if you use each address only once then you're taking full advantage of Bitcoin's inherent privacy features.
4) Is there any way to coinjoin/mix/whatever so that the output does NOT LOOK tumbled? Or run each UTXO afterwards through various further transactions (hops?) to hide the trail? Does that term "hop" mean a transaction that just moves those BTC a bit further along?
Not that I know of, but you could use a P2P exchange to trade your bitcoin for bitcoin with a different transaction history. Personally, I use Bisq to do just that. I trade my bitcoin for Monero, then trade that Monero for someone else's bitcoin, effectively breaking the traceability of my transactions by replacing them with someone else's transactions.
5) Do the desktop hardware wallet apps for Ledger, Trezor, BitBox, etc. (also the desktop hot wallet apps) run through TOR (if I am running TOR on my desktop, or even running Brave)? I have not been able to dig up that info myself. Is running TOR when using these apps even worthwhile, or is a VPN good enough?
I can only speak about Electrum, Sparrow, and Trezor Suite since they're the only ones I've used extensively. All will allow Tor connections, but you need Tor running as a service. If you have the Tor Projects browser installed it'll run Tor as a service while the browser is running, but it shuts down the Tor background service as soon as you close all the browser windows. Tor Project's website has instructions on how to run Tor as a background service for Windows and Linux. It's a very light daemon, and uses very few resources, so there's no reason not to have it running by default as soon as the computer boots up.
Good luck.