I think health professionals tend to want to wait to see if the lip tie will stretch since it is a tie that can and often does rather than just cutting it straight away 'just in case.' My son does still have a minor gap in his teeth but not anything I'm worried about, if he needs braces he needs braces. His teeth are a pain to brush but not enough for me to look into it more (it's a pain to get him to open his mouth to brush them period) and being that he is only two and it has stretched heaps the last year I feel confident it will continue to do so.
Bbhope, once you decide on a dr about his tongue tie just speak to them about their thoughts on his lip tie, doesn't have to be anything you stress about now unless you think it's contributing to his feeding issues.
As far as the regression they're pretty awful😕. If you google '4 month sleep regression' and 'thebabysleepsite' she has a bit of advice. X