Nice job man. I may have some answers to your questions. Since it’s very difficult to get unstuck once you’re already in a stutter, do whatever it takes to change things up. For example, use a synonym or rephrase the sentence so you can approach the word at a different angle. Another method that could help is whispering the word or skipping the first syllable of the word entirely for example saying hool instead of school, it sounds more natural when you speak it, but that’s just something to try out. About the one stutter messing up your whole speech: A tactic to get around that is to pause and take a deep breath for at least five seconds. This will reset you and hopefully put you back on the right track. Anyways, great job and keep it up.