I totally agree with everything MushyMilk just said - also CONGRATS on baby number 2!!

I do know of a lot of people who cosleep with more than one baby if you feel strongly about it! But obviously do what's right for you
Anyway...at the risk of bombarding you with information Ecoden, here's a few articles that I think you'd be interested in. It might look like a lot to digest but it's definitely worth it!
https://sarahockwell-smith.com/2014...hen-you-teach-a-baby-to-self-soothe-to-sleep/
https://www.itv.com/news/wales/update/2015-05-19/new-research-finds-babies-should-wake-at-night/
https://www.kveller.com/five-reasons-why-mayim-bialik-doesnt-believe-in-sleep-training/
https://www.psychologytoday.com/blog/moral-landscapes/201507/baby-crying-dont-shame-the-parents
In short, the best thing you can do for your baby is to meet her needs and respond to her cues. The most reliable way of ensuring that she grows into a confident, happy, independent little girl is - surprisingly for some - to let her be completely dependent on you in the early years. So many people seem to think attachment parenting (which is basically what I'm referring to) breeds clingy, dependent, needy children but this couldn't be further from the truth. In fact it's quite often the reverse - babies who are sleep trained can go through intense regressions, and parents often have to go back through the whole process from the start, if they have the heart. I am living proof of this! When I was a baby the done thing was CIO. My mum did it with all three of us. Not only did it not work for me (I actually remember standing at my babygate at my bedroom door crying for my mum and dad and trying to climb over), I also think it has played a major role in a lot of the issues that I have today, eg. anxiety, low self esteem. Also I always used to want to go and sleep in my mum's bed, up until I was leaving primary school, which I often wasn't able to do 'cause she often had a boyfriend..
These early days will go by SO quickly, and I for one know I'd rather look back on them knowing that I was always there for her when she needed me rather than just when it suited me, which is essentially what sleep training is. Sorry if this sounds blunt!! It's just hard to sum up my feelings on the matter without doing so!
Here's a link with some general info on attachment parenting and lots more interesting links:
https://www.askdrsears.com/topics/parenting/attachment-parenting