'Pull off' is not a simple synonym of 'succeed' - there's more to it than that. Of the 4 sentences you've given, only number 2 seems natural. It might help to think of nouns which collocate with 'pull off' in this sense. The usual nouns are [pull off a..] trick, stunt, prank, deception, and similar ideas. If you pull something off, it suggests that you've managed to do something rather clever: 1) despite the odds and despite people's expectations and 2) with a certain style and 'panache'. This is why we often use it when we talk about fashion e.g. "Not many people can wear lime green and crimson together, but Fifi pulled it off. She looked fantastic." This ticks both boxes - both the surprise and the stylishness. Instead of trying to invent your own sentences, google some real examples from genuine native-speaker sources. That way you'll get a feel for what we really mean when we use this phrasal verb. By the way, your problem typifies the ineffective way that phrasal verbs are often taught. The classic way that a badly-trained teacher or ill-conceived coursebook deals with phrasal verbs is to give one example, a supposed translation (along the lines of the hopelessly reductive 'pull off = succeed' ), and then students are sent off to invent their own examples. You'll never learn that way. Forget about trying to define the 'meaning' of phrasal verbs. Instead, you should immerse yourself in as many real-life examples as you can with as much context as possible. That way you learn the language in the same way that native speakers do - through context.

I agree 100% with Su. Ki.'s explanations and examples. And her advice is really excellent too. For further information about this phrase and others, here are links to two websites that may help: 1. Look at Number 3 on this page: https://idioms.thefreedictionary.com/pull+something+off 2. Scroll down to "pull off" on this page: https://www.usingenglish.com/reference/phrasal-verbs/pull.html#Pull-off I highly recommend these two websites to my students when they are struggling with phrasal verbs (and idioms). They are both full of useful information. Also, you may find the two Cambridge series "English Phrasal Verbs in Use" and "English Idioms in Use" very helpful as well. They include the phrases, their meanings, and example sentences, along with explanations of when and how to use them.

Every time I try to make up a sentence with "pull it off", I seem to find a better option, like "managed to do it" or " I made it" and so I can't get it so far when "pull off" could be a better option...