Congratulations on your third baby! If it were me I'd use another boy name that had an 'ay' in it or at least the same sound, and I think that Mayson Edward flows well and sounds lovely. From your girls combos I think that Aubrey goes best with your sons names, but Madilyn is my favourite of the two. Hmm, other suggestions...
Boys: Jayson, Brady, Grady, Taylor, Baylor, Sailor, Raymond. (I like Taylor the best from these, it has the same sound as Jaycob and Ayden, but it feels a lot different, and Taylor Edward is very handsome)
Girls: Isla, Pippa, Rylee, Blair, Brooke, Josie, Wylie, Laura. (I think Pippa sounds lovely with your sons names, although Pippa Shea and Pippa Lynn don't flow well. What are your thoughts on Pippa Madilyn?)
In short, my favourite names to go with your sons would be Taylor Edward and Pippa Madilyn, but from your suggestions I like Mayson Edward and Madilyn Shea.
Good luck choosing!