Yes

Not your keys, not your coins. Applies everywhere.

Yes, owners of site definitely could, if they want to. In fact, you don't have sats here, you have IOU against sats. They become your sats only after you withdraw to non-custodial wallet where you control private keys.

This is probably just me being pedantic, but SAT isn't an acronym, it's an abbreviation for satoshi, so it shouldn't be capitalized.

Do you see any seedphrase?

Yes, @nemo will with his shitposts :D

You mean, like it could happen with the fiat in your bank account? :D Btw yes, it’s not a non-custodial solution. If the website/node disappears, “your” sats disappear with it. If your login details get leaked, bye bye sats

Yes, you can always be rugged so don't hold more than you're comfortable with