We were at HNY middle of March.
Can't comment on the cereals as I didn't see what was there, but my friends 5yr old had some sort of chocolatey cereal - not sure what it was, choco flakes maybe, sure they weren't cocopops lol.
There was a selection of yogurts and I think there was fruit (can you tell I wasn't really with it at 7am

) but there was definitely bacon, sausage, scrambled egg and those sliced potato thingys

plus sliced cheese and cold sliced meats.
A selection of rolls and pastries including the ones with chocolate in. Plus the little pots of jam, marmalade and nutella. There was also sliced bread, so you can do toast - the toast machine takes ages and only does one side at a time
Fresh orange juice, I think the other juice option was apple. Plus the usual selection of tea bags and coffee etc. The juice, hot water and milk are all in machines, the type you put your cup under and press the buttons/lever to dispense. I'm sure there was also bottles of water - I vaguely remember seeing largish glass bottles - I presume they don't do the smaller evian ones to stop people walking out with them
I love their crusty rolls

and the bacon, eggs and potatoes are yummy too.
We were in the parkside diner every morning as there was also a conference on the week we were there. We had a 7am slot everyday and it was never busy or rushed

Except for one morning when we were late, we got there at 10.20 and were sent into the manhattan, same food just different seating layout. They didn't have a problem with us turning up late, even though breakfast finished at 10.30, there was only 2 other families in there with us, even though it was close to closing time the selection of food was still good and everything was still fresh.
Hope that helps