If you're expecting twins, then you can keep soft toys in pairs (like 2 elephants, 2 rabbits, etc). Purchase dolls and come up with creative ideas to make unique centerpieces with word blocks. You'll also find themed medallions in stores which are sold exclusively for decorating baby shower tables.
The first option is, draw smiley faces on the balloons and fill them with glitters and petals. When the balloons burst, the petals will shower on you. You can also attach the balloons with the stuffed toys placed on the table.
It's better to make arrangement for dining on a separate table so that there's no paucity of space while serving food. Keep a collection of edible party favors on the dining table for your guests.