there are still night feeds happening and he already takes way more than the suggested amount of milk through the day. He's also now on two big meals a day. His last feed at night is 9 and a half ozs so he's definitely not hungry
There was a time (between 5-7 months) when my 91st centile baby was drinking nearly double the recommended amount of formula in the daytime. At her maximum she was having 7 or 8 7oz bottles in 12 hours - so up to 56oz. From memory I think the maximum amount on the side of the SMA tin was 5 6oz bottles in 24h.
But if you are confident baby is definately definitely not hungry at night, which is reasonable to assume given what you say, why don't you just... not feed?
I don't mean to be flippant, but if you know a night feed isn't needed and you know baby has alternate comfort avaliable (dummy and comforter), you dont need a sleep trainer's permission to stop offering milk at night and settling without milk. Yours appears to be a different situation to a baby who needs to feed for comfort or a baby who needs the calories.
I would park myself next to the cot (pref cot next to my bed) and just keep continually offering in-cot touch reassurance and dummy reinserts, but resolutely not feeding. It's not going to be amagic wand to stop night wakes, but it's a start. You cant expect night wakes to stop until night weaning is established, so it is a necessary first step.
As for night time pooing, it's probably just changes in digestion and will go away on its Ian. It is a good idea to make protein (meat) meals at lunchtime though. Make evening meal carbs heavy.
And I'm all for full-steam-ahead cracking on with weaning solids at a rapid pace.