I would go Julia if your mum hasn’t had a mention before and b/c presumably the last name comes from your husband’s side. I also like the three syllable into a one syllable, and the lyrical & lighter quality about the name. You could use Rosie (and Romy) generally - and then Rosie-Jay & Rosalie / Rosalia as household nicknames to tie in the middle. (How important is it to honour your mother? And would she be cool if MIL honoured?)
That said, Rosemary Louise is more familiar and rolls off the tongue a little easier, and gives you Rosie-Lou. It looks a tad more cohesive on its own and stylistically with your set. I also like that it doesn’t repeat the j of Jesse but that is really getting finicky. Less finicky, if your last name is Sm*th, or an S last name, Julia is a better flow. In other words, it does depend on last name!
Another option is Louisa as a smoosh of Louise and Julia. But not sure your mum would take that as an honour!? I like the rhythm of Louisa with a one syllable last name.