we are slow on the implementation of the solids but I don't want to rush the latter as I can already see food sensitivities with his skin etc.
I wouldn't worry about this. Solids before one are just for fun & exploration:) I went super slow too as I was so worried about her not having enough milk. We only did breakfast for ages.
I will think a bit and write more later but my first thought was that you are probably in the 3-2 transition. I think you are right about A times needing to be increased. Going for an EBT instead of a CN is a good move. But there can be a lot of accumulated OT during this phase, which can lead to NWs soon after BT. With us, DD would sleep off just fine and then need multiple resettles. It took around 2 weeks to get over the OT.
All about the 3-2 transition- 5/6 monthsThere is also a major growth spurt at 6 months. Do you think that's it? He might just be hungrier than usual. It was around this time that I realised I had to change feeding routine - I was also doing the top up feeds half an hour before naps. Instead I started giving DD porridge - oats, fruit + 2 oz milk -- this way it was light on her tummy and I was getting more milk into her too. I still nurse twice in the second A time but I leave a 3 hour gap to bed. It is possible instead of feeding more often, spacing feeds out would lead to him eating more. The best solution to tackle NWs due to hunger are to increase calories during the day - so bigger feeds, adding milk to solids, solids like yoghurt, pudding..all good.
I hope it is just a growth spurt, which is passing & you get more nights like yesterday. Sorry if I wasn't too much help