The best online official dictionary is the CNRTL, but it does not include translations and it’s difficult to read even for French people.
The Wiktionary is also very good and contains a lot of translations, conjugation and grammar pages. (and it’s free!) (searching both on the French and the English versions is better)
People often think of the Larousse or Le Robert as references, but they are less complete than CNRTL and Wiktionary.
The Académie posts some articles about difficult subtleties of French language, but they are usually one century late, pedantic, conservative and irrational. The Quebecois equivalent also posts useful stuff (used as a reference by grammar nazis).
The use of punctuation is almost the same (except for decimal/thousand separators, which are inversed), I think this is not a problem.