I have tried PD successfully in the past, but recently it seems to rile him up more. I've never done CIO. However, last week he had a couple of really bad nights where he screamed for 90min or so, no matter what we did - and when I say that, I mean that we tried our usual methods of soothing (shushing, hand on him) without taking him out of the crib. But by the third night I was so exhausted, I threw in the towel and slept with him in dd's bed while she slept with dh. (My dd and ds share a room and she was getting disturbed by the screaming.) Ever since, he is a nightmare to put to sleep. Before that night, he would go down very easily for naptime, with just me standing next to his crib. Now he fights me doing PD; it seems that one night made him want to be held all the time!
We also have been trying a slightly modified routine for the past week. We were battling 5am wakings; WTS didn't work because he was waking at 4am also. I had journals of my dd's routine at this age and she was going down later in the evening and waking later too. So I've been putting ds down a bit later and he is now going back to sleep until 6:30am. So here's pretty much what we're doing now:
4:30am - wake, soothe with hand on back, asleep quickly
5:30am - same, although sometimes he skips this waking
6:30am - up for good
7:30 - breakfast
11:30 - lunch
12pm - start nap routine
12:30 - asleep
2:30 - awake (usually, although the past two days he's napped very poorly)
6pm - dinner
6:30 - bath, then play
7:30 - books
8pm - asleep
10pm - every other night, this is when he wakes and nothing seems to help at first; we don't give the sippy right away because dh thinks ds can go without it; eventually, I give in because I can't stand to see ds obviously want a drink and after he gets it, he goes right to sleep
Of course, writing this all down, it makes sense that he's having some difficulty because we slightly changed his routine at the same time that I threw him a loop by sleeping with him one night. He had a very tough time going down for his nap today, but I realized I was starting the winddown very close to the time I did it during the old routine, so maybe I need to move it a bit later...
Anyway, the sippy cup issue still stands. I don't think that giving it to him will make him dependent, but what do I know? Neither of my children slept well the first two years, so I've definitely made mistakes before!