Personnaly, I’m using space bar in all the cases you’ve mentioned. Except sometimes before the percent sign.

I use a non-breaking space (that would be option+space on my OS). It unfortunately is often wider than it should be, but I don’t know of any convenient way to type a narrow non-breaking space.

A bunch of questions on this site already address the usage of spaces around punctuation in French. For instance:

• Which space should one use before punctuation ? Does it depends on the technology?
• Pourquoi place-t-on une espace avant les ponctuations fortes ? — Why is there a space before certain punctuation marks?

More can be found browsing the typographie tag.

Usage varies among countries. In France at least your observations are correct; all “high punctuation marks” are preceded by spaces (some are thin spaces) according to standard typographic conventions.

(I’m not sure about %, which is not punctuation. I can only say that it is not commonly preceded by a space on electronic support. Some thin space might be found print, though I’m not sure; this needs to be confirmed.)

A large majority of French speakers from France use a space before a question mark, exclamation mark, colon or semi-colon, both in handwriting and typewriting. On a keyboard or on a phone most would use straight English quote marks (without spaces) because only those are available on a traditional keyboard. However, whenever one chooses to use proper French quotation marks, inner spacing is added, — let me say it once more — in France.

To sum it up, and now I think this statement is compatible with Switzerland, Belgium and Quebec usages as well, whenever a thin space would be expected in print, it is commonly replaced by a normal space when typed on a keyboard. Software is sometimes able to transform this normal space into a thin unbreakable space when appropriate.