Which is better, 其他所有 or 所有其他？ 其他所有 or 所有其他，which word order is more natural and ”合乎中文的习惯” ？

For example, as in 其他所有内容 or 所有其他内容， 其他所有人 or 所有其他人， etc.
Both will be fine. They have a different emphasis and usage for the context.

When you say 其他所有, you are emphasizing "others" and 所有 isn't got special attention. The felling will be similar to "The guests today include faculty members from the math department, physics department, and all other departments from south campus".

When you say 所有其他, you have a special emphasizing of "all". It's like "Every person leave, please. EVERY one."