Is this going to be your first time to Hong Kong and Macau?
Citygate is not a must-go place, but I normally have brunch there (there's a foodcourt upstairs) before heading to Lamma Island. Then when I return, I'll just browse around without any fixed timing coz I'll just go off if I don't find anything interesting or worth buying.
No harm giving it a quick walk-through if it's your first time there. Same for Macau, a 1-day trip is possible, just try to start off early and don't plan for any important event in the evening that you've to rush back to Hong Kong.
It depends how thorough you want to cover those places that you've in your list. If you've anything specific you want to get/look, then give it more time. Otherwise just be prepared that you might end up doing a touch-and-go with some places.
I know the forum and elsewhere have suggested places to visit, but know that it's not possible to cover every one. Breakfast can be taken in the many eateries around your hotel, so you don't have to deliberately travel to one end for breakfast then travel again to a place of interest.
Don't feel too disappointed if you've to change anything on your itinerary at the last minutes - bear in mind that you're on holiday, take it easy. There's always another chance for you to go back to Hong Kong some day.