I also ran it while browsing with ungoogled-chromiun in Debian with ublock origin in “strick mode” and there wasn’t a single sound. I didn’t try your tests but I have a lot of google domains that I added over the years in the uBO rules to block them, like googleapis and stuff like that.

There isn’t AFAIK, but there is a Firefox add-on that I guess it should work on android at least for web browsing.

You won’t have to try the combinations of 250 words because the seeds are words at equally spaced distance so at most you have to try 20 combinations. And that’s supposing that all the 250 words are from the seed list, which obviously is not going to happen, so you only have to try a few valid combinations if you forget the number 13. So all you have to remember is the title of the essay and that the seeds are equally spaced, and even the later is not necessary if you think about it just a little bit (just don’t use words from the bip39 wordlist for the rest) and I expect that you are not dumb enough to save the page in only one single place among thousands of other pages. If you want you can save the page in the same way you would save the 12 words, may be with a couple of other documents, but the point is not saving a paper with just 12 words!

Absolutely. All you need to recover your keys are the 12 words. Never save the 12 words alone, If someone come across them it will be obvious what they are. Write a little essay of one page of length or less about whatever topic and hide the words in it (like every 13 words or whatever method you like that its easy to remember). Nobody has to know that you save your keys in this way. For me the key to save the seeds safely is disguise, simply because they are just words and its easy to do it. Hide the essay among other documents and that’s it. If nobody knows that that’s the way you save them there is no way they can figure it out. That way you can leave them in many places for additional safety.

The coins are on the blockchain, what you save in a wallet are the keys to access them.

Contrary to the common believe you don’t need a hardware wallet to keep your keys safe, what you really need is a air gapped or cold storage and you can achieve this in many ways. I found that one of the best ways to do it is grabbing an old phone and following this guide

https://medium.com/@fbonomi/a-bitcoin-cold-wallet-based-on-qr-codes-e8c130b3181f

Tldr: install the wallet and never connect the phone to the internet again and use QR codes to sign transactions using the camera. Super practical, cheap, truly air gapped and doesn’t attract attention like a hardware wallet. Additionally I would disable the wallet app when you don’t use it, so the wallet will not be visible in case someone else grabs the phone (you can do this by installing the app as a system app using adb). And don’t forget to save the seeds of the wallet in safe place and always use fully FOSS wallets like electrum.

You want a debate posting homepage links? At least take the time to post a brief summary of the main points concerning the issues for each language. At the very least the actual links where the information is located.