I weaned first then tackled the co sleeping.
I commenced weaning my son when he was 27mths old (in October, fully weaned by 18 December).
I started slowly on advise of ABA. I first tackled the lunch time feed (before his nap). I would lay down with him on our bed until he drifted off to sleep. I tired him out that morning with park, games etc which helped him go to sleep quickly. I also encouraged him to eat a big breakfast/lunch. This feed wasn't too bad to cut out.
I have lengthy notes on his reactions each day but thought I would give you the brief version.
Next week I tackled the morning feed (upon waking). This one came with tears but I just cuddled him told him I loved him until he settled down. I then offered cows milk and a breakfast he enjoyed.
The last feed was the one/s before bed. I commenced these about a month after stopping the morning feed (it was hard for me to have that last feed ever). Again there were tears but to my surprise only the first night for less than 5mins then he rolled over and went to sleep. I laid awake sad lol.
A couple of times during the day he would try to sneak a feed in and then crack up laughing cheeky monkey. Considering he was a boobaholic he did really well with weaning, I was pleasantly surprised.
Next was the getting him back in to his room. We decided to convert his cot to his toddler bed, to make it exciting/enticing. I started on a Friday night so I had DP's help if needed. I have been laying in his bed with him until he drifts off then I leave. The first couple of nights I was reading to him in there but he wants book after book and I find it stimulates him. He is better with lights off, a hallway light just shining through and letting him know he can roll over and go to sleep.
1st night took 1.5hrs. Jumping up and down on bed, telling me he is a boy and daddy is a girl
, telling me he likes me/ loves me etc etc until he crashed.
2nd night 1hr until asleep.
Next night 30mins.
Next night I was at work and he went to sleep in 15mins and has mostly done that since.
He sleeps the whole night in there which I didn't expect. He has done really well.
I hope some of this helps. Sorry so lengthy, good luck.