Hi Anna,
You know I need certain things when I go to sleep and bubs are the same. Many babies find music or white noise calming. Find what works for your bub and don't worry about it too much. They all grow out of this stage. I found the worst thing I could do was think that it was something I was doing or not doing that determined whether he slept well but it really just comes down to them. Some things help like a wind-down routine, some milk, a blanky etc., music and if something does help then Great!!! Don't get too caught up with labels like 'self-settling' cause they are all open to interpretation anyway. Just try and give them what they need - like a cuddle from mum - because that is all you really can do. We still have DS (13 months) on our lap to sleep for his day naps (better than rocking cos you can get some extra cuddles and watch tv) but for his night sleeps we have a small routine where I tell him a story while he has his bottle and we watch a light projection on the roof with some soft music. He then goes into his cot awake and goes to sleep himself to the music. I love music particularly because it can be transferred from one person to another like you mentioned.
Good luck with it all!