Thank you very much for your New Year's greetings!

I'll see if I can help you with your questions.

1

I can't tell you if and when the checkbox will appear. I'm now protecting my pages with Cloudflare because of numerous bot requests. Before your request is forwarded to my server, Cloudflare checks whether a human is sitting in front of the computer or whether the request is coming from a bot. I can't tell you exactly how it does this. I suspect it's based on mouse movements or scrolling or something else that human actors do when they're working at the browser.
Just today, bot activity has increased significantly again:

To prevent my servers from becoming overloaded, I have to block bot requests. That's why users like you see this checkbox.
If the check was successful, the page should load just as quickly as before. Unfortunately, I can't tell you why it's taking longer for you. Perhaps it's due to your internet connection.

2

We have observed this behaviour when someone uses the current Keychain extension. Is this also the case for you? We have already discussed this with the developer. It is exactly as you describe. The extension does not wait for feedback from the chain that the operation was successful. The extension then reports the successful operation back to the page. At that moment, the page loads the current data from the chain, which has not yet been processed there. This is why your vote is not displayed. We have reproduced this in detail and already communicated the solution. As far as I know, it has not yet been implemented.

3

For a witness node, the internet connection must be very stable and have low latency. Each witness node is located in a p2p network that constantly exchanges data with each other. This is very time-critical. Remember that a new block is generated every 3 seconds. The witness whose turn it is to generate the block must create it in time, otherwise the block is considered missed. This is not good for the stability of the blockchain.
I would also not recommend an HDD. The node constantly generates read and write accesses to the disk. Every 3 seconds, a block and some operations are saved to your disk.
A changing IP should not be an obstacle, as you are constantly communicating with the p2p network anyway. However, the internet connection is interrupted when the IP changes. This is more critical, as your node then has to reconnect to the network.
I checked the data volumes (for 24h) on my provider's site (only the witness node runs on that server):