Hi there - your routine looks great!
You probably already know that milk remains the primary food until 12 months but so long as he doesn't drop his milk intake too much or too rapidly it's fine to offer more solids. Babies are pretty good at self regulating so if he appears to want more then I would offer more. Often LOs might not take a third meal until closer to 8 months but if he's keen then I would follow his lead (with the proviso he still takes enough milk), you could either increase what you offer at the 2 meals you already have or introduce a solids lunch at 12 noon. You might consider making something out of breast milk, a simple milk pudding for example or custard (if you pump that is). At 6 months (or now if you feel he is ready) you might want to introduce some finger food, this could satisfy his desire for exploring and tasting solids without so much going in leaving him hungrier for milk.
Some babies take to solids very quickly, mine ate solids like I'd been starving him for the first 5.5 months of his life, I was quite surprised. Others aren't so keen on solids until much later, either way it's fine.
WRT milk being at 4hrly interval that's ok too. The 4hr EASY (which Tracy described as starting in the fourth month) has 4hrly milk feeds. Some babies might not transition happily to 4hrly E but most will by the time they are 6 months. Don't forget he isn't going a full 4hrs without food as he is getting a little solids now too (many extend the E at 6 months+ once solids are introduced and go longer than 4hrs, depends on the routine and how long naps are etc too).
Looks to me like everything is fine and your DS is enjoying exploring the new textures and flavours you are offering him.
hope this helps.