Hi Nikki,
That sounds exactly how my lo was - also all over the place with his naps etc. I say yes I do think that he is eating enough during the day as he would let you know if he was hungry. When I switched my lo onto the 4 hour easy, I was worried that he was not eating enough as he was only having 4 bottles a day, but he is still sleeping through, so must be quite content.
What I did was, if he fell asleep and was due a feed, I would wake him up for his feeds so as to not get out of routine. Usually after his feed he would go straight back to sleep.
I know they say that you should not wake your baby up when they are asleep, but this enabled us to get into a good routine, and now he is always awake when his bottle is due or wakes up about 5 minutes before it is due.
I would not worry about the short sleep periods, my lo has never been much of a sleeper during the day, and usually on has about 3 naps a day, and these are really short, sometimes only lasting about 10 minutes - I call these his power naps as they really seem to refresh him.
If your lo is waking in the early hours of the morning, I would definitely suggest a dream feed then - this may enable you to get him to start sleeping through. If this routine works for you - giving him a dreamfeed at around 11 - you should be able to slowly start reducing the amount you give him at night and then he should start sleeping through.
What I ususally do on my lo's last bottle is give him the option of taking a bit more i.e. I make up a 9oz bottle instead of an 8oz - sometimes he takes it and sometimes he leaves it, but it does help him last that little bit longer at night. I also changed my lo onto the 2nd stage formula for hungry babies, and this also enabled him to go a bit longer.
Hope this information, helps - Let me know how you get on.
Regards
Paula - Mum to Thomas