19: Colour and Style Q&A: Blazer for H Shape, Flattering the Back View with a Long Rise, Using a Necklace as a Lynchpin

Short waisted, large bust H shape what to look for in a blazer so I don’t look rounder and bigger?
How to dress a long rise high waist low rear body so the back view is flattering?
How to create a lynchpin within an outfit using a necklace with the colours of your bottoms?