It gets exceedingly tedious for me to have to keep saying this, but the basic problem continues to remain:
Different people use the word "to failure" to mean different things and usually there is NO WAY to tell from the context what they mean.
Therefore, anyone replying to you may have read your post with interpretation totally different than what you meant, and when reading anyone's post, you may interpret what they are talking about totally different than what they meant.
Many people routinely use the phrase "to failure" for a set where no failure of any kind occurred, every rep attempted was successfully lifted and in proper form. They call it "to failure" because the last rep was hard, or because they guess they couldn't have gotten another, or because -- not actually putting in any blood and guts effort -- they decided to let the spotter help on the last rep.
At the other other extreme, other people use the term "to failure" to refer only to that condition where you damn well keep attempting reps till steam comes out of your ears, and if the bar stops you damn well fight with every drop of energy you can find in your nervous system to try to get it moving again come hell or high water. And if it doesn't move further upwards then that is only despite your absolute utmost effort to make it do so.
These are two totally different things.
There are also intermediate meanings.
The answers to your questions depend totally on what you mean by the term -- and no one has any way at this point of knowing what you do mean -- and whether a given answer is applicable to your questions depends on whether the person replying has the same meaning in mind that you do, which again we have absolutely no way to know.
It's not your fault: it's just a common phrase that causes far more miscommunication than communication.