Το πρωινό δεν έχει καθόλου σκόρδο=Breakfast has no garlic at all=Breakfast doesn't have any garlic.
Yes, this is something I've come across on other courses as well. Sometimes, the sentence you have to form with the words given contains an apostrophy alternative (doesn't instead of does not, isn't instead of is not etc.) It's not wrong. ^.^
Δεν is for a negation, it goes in front of a verb, if i remember well :)
It does go in front of a verb, but only in the indicative mood. For subjunctive and imperative use μη(ν).
The Greek should try the toast rubbed with garlic and pour olive oil. Pure Mediterranean.