Hi Inga,
Sorry you're having a bad time, its times like this that I absolutely hate being a mother. Anyway enough about me. I am not an expert but have been using the GF method from about 4 months. It worked for Hassan v quickly because I think he was starved from breastmilk!! In your case, I think it may take longer to establish a GF routine in a baby of eight months. So please don't get stressed because it must be a massive transistion for a baby.
The night time problems may be happening as a result of the day time feeding. If your baby is not eating enough solids, or drinking too much milk during the day (at the wrong times) he may be genuinely hungry at night. How much does he drink at 2.30am? If it is more than 5/6 ozs then he may really be hungery.
The routine should be something like this. Give milk at waking (6-7am)then breakfast should be between 7.30am and 8.00am no later otherwise affects lunchtime appetite. Try ABSOLUTLEY no snacks until lunch apart from some juice/water at 10insh. Lunchtime about 11.30 to 12.15. When he wakes up from midday sleep offer milk. Don't feed after 3.15pm and don't let him sleep past 2.45ins. Tea at 4.30pm to 5.15pm. then milk at bedtime. I know it is bind but be over regimented about this and the method actually gets babies hungry and ready for food.
If you follow the food plan properly you will know he is defintely not hungry when he is sleeping.
In terms of the morning nap and mid day nap. Look on page 139, between 6 and nine months some babies unfortunately start to drop their morning nap. To make sure, it isn't that, check what time he is actually waking up. For the morning nap to work you need to make sure he is up before 7.00am. That gives you atleast 2hrs thiry minutes to tire him out before 9.30 nap but if you let him sleep longer then the routine will naturally move forward affecting the whole day. If he is still not sleeping by say 9.45, he may want to drop the nap completely, in which case let him and that should help to completely knock him out for 12.30 nap.
Try not to get too obsessed with the sugar thing, I was but found that after 12 months their apetite declines anyway and then you'll start to give them sugar and salt anyway.