On the manipulation front, our daughter is nearly 4 and most nights she wakes up and comes to our room to ask if I will come to her room for a cuddle and to sleep with her. TBH, I pretty much go ahead and do this most nights as she just goes straight back to sleep (I have a double bed in her room).
When she stays with grandma or her cousins, though, we always have the 'talk' about how it is nice to not disturb other people in the night and how she needs to try and sleep all night long, blah, blah. Nearly 100% of the time when she is staying over with someone else, she does sleep all night and not disturb anyone. So, without a doubt, she is 'manipulating' me. However, I have come to the conclusion that she should *always* know that I will be there for her, including in the middle of the night. Plus, I quite like those middle of the night cuddles. BUT, I am barely awake and get on average 7 - 8 hour sleep a night, so it is not a problem for me.
My 'solution' is not for everyone, but it works for us. However, it took us a long time to get to this stage - we had the 2 hours getting to sleep stage, the wake for 2.5 hours in the middle of the night stage every night for months stage, the stalling tactics stage... you name it.
My way of coping has been to remain calm, remember it's not forever, and try to get as much sleep as I can so I can deal with it. You *will* be able to cope and, if you are consistent and calm and try to be rested yourself, you *will* see improvement, even if it takes months (years!).
I also highly recommend wi/wo like previous posters - this is something that has worked really, really well for us, particularly for actual bedtime - I remained right outside her room and pottered about doing things. At times I needed to go in and give cuddles, but I only did it for a while.
Now, though, she goes to sleep in about 10 mins flat, but I now stay in her room and read stories - we are onto quite long chapter books, so I actually really enjoy this special time with her and do not grudge that tiny 10 mins of time. Sorry for such a long post and sorry it's really about me - I just want you to know that whatever you do you will be helping you LO on the way to good night's sleep. xxxx
PS Just re-read your post and remembered you are doing wi/wo. Maybe you need to adapt it a little -- not sure exactly how, but try tweaking what you do / say and seriously consider that earlier bed-time - you might just catch a better window for him and he will go to sleep quicker and stay asleep longer - can't hurt to give it a go. (hugs)