I'm with you on the big baby... mine is 6.5mo & over 22lb :lol:
By the way it is very normal for babies at this age to be fine for a while & then after rolling around etc, get upset as they have got overtired...often the long time to settle means you may be putting them down to early... I find I need to wait until my ds#2 is tired, then read a few stories & allow at least another 10mins before I put him down... I tend to walk around the house or outside to just get him to 'unwind' more
I do think Pu/pd would be a good idea if he is used to being held to sleep. I haven't ever done it... I didn't discover BW until my ds#1 was sleeping ok & #2 settles well with Patting so I can't offer advice. There is a forum for Pick up /Put down, so you might like to post there for advice.
I think as far as a set routine goes... try to pick times for your day naps that you ideally want them to be & work at trying to get them to happen, even if that means you have to keep him up longer for the first nap... say you want it to be at 9am, but because of the early wakeup it is more like 7.30, well try for 8am for 3 days then 8.15 etc & do the same with the 2nd nap & bedtime.
HTH