If your waist and belly measurement is bigger than your bust, then you are an oval shape.
There are too many rules for oval shaped people, such as " no bright colours, no big print, no polka dots, no horizontal lines". It feels like no fun and almost a punishment for only few choices of styles.
After I had a look at plus-sized fashion model Ashley Graham and funny FATshion blogger Lolly's profile (lollylikesfatshion.blogspot.com), I realised that plus- sized fashion could also be dynamic and chic. The key is to embrace your body and be confident. Sometimes, adding eye-catching details on make-up such as scarlet red lipstick or accessories like glasses or handbags, can achieve a great result!
As for brides, apart from tightly fitted to knee length mermaid style should be avoided, I believe curvy brides can rule almost any styles. If you want the waistline to be more accentuated, having a belt can do the trick. If you'd like a more defined figure, having a inner corset could really help.
For mother of the brides/groom, long jacket with soft draped fabric would be the best choice.