Thank u to you guys who have answered!
Here's the direct choice guide to get ending 3 and 4 (I'll put it under the cut in case people want to figure out it out on their own :)):
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After the Stage 2 mark, choose all 4 options that show your interest in finding out more about Chao, including the kiss. Choose:
1. Dig deeper
2. They want to tell you something
3. There's something more
4. Kiss him/Let him kiss you
It'll automatically lead you to the branch leading to ending 3 and 4 :)