Hi there
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Your LO is still quite young and if he is happy on the 1hr A time then that's fine. Soon enough he will be able to stay awake a bit longer and that will naturally help to extend those E times. So for now if he sleeps 2hrs that fine and brings him up to the 3hr E, but if he sleeps 1.5hrs after the 1hr A time you can go ahead and feed him at 2.5hrs.
There is no "rule" to feed LOs as soon as they wake, this is based on whether they are hungry or not. It sounds like he really is hungry, go ahead and feed him and if the routine goes a bit off track that's okay. If though he begins not to be so hungry at the 2.5hr mark you can slowly extend the E time which means there may be a little A time after S and your routine might look like EASAEAS which is also fine.
My DS was on 2.5hr E when I discovered the BW books when he was 4 - 5 wks old and I started to slowly extend his E times just by 5 mins each day. Every baby is individual and eating regularly, a proper feed, at 2.5hrs is perhaps just what your LO needs right now - this isn't the same as snacking.
Don't stress yourself out trying to make those naps 2hrs long though. 1.5hr is fine and considered a restorative sleep. All the routines in the books are guidance only, I've often found on the boards babies either sleep 1.5hrs or 2hrs but rarely mix the two or move to one if they naturally do the other.
In terms of how much day sleep effecting night sleep - don't worry until there are signs that it isn't working. If your LO is up half the night ready to play then something needs to change. There is more likely to be a problem with night sleep if LO is allowed to do a 3hr+ nap as this would indicate that his "long stretch" of sleep would be coming in the day time rather than at night. This is clearly not happening.
With 2.5hr E and 1hr A time your routine might get a bit trickier as the day goes on. It could look something like this:
WU 7
E 7
A 1hr
S 8 - 9.30
E 9.30
A 1hr
S 10.30 - 11.00
E 12 *** instead feed at 11.30 - see below
A 1hr
S 12 - 1.30
E 2pm
A 1hr
S 2.30 - 4
and so on
*** so at this point things get hard. You can't feed at 12 and have LO asleep at 12. So you would need to bring that E time a bit earlier, say 11.30am which is only 2hrs and you would need to put a little A between E and S to avoid making a F2S prop (feed to sleep). As I say though, soon he will be able to stay awake longer so don't worry too much about a perfect routine right now.
Hope this helps