As far as how much you need, that depends on the size you want to make, I used 1 1/4 yard for my 2 year old Fabric for the lining, the same amount as the outer fabric Something to fasten the cape, I used a toggle, but you could use something like a ribbon to tie or a button and fabric or elastic loop
Considered a more casual fabric, youll find that many button down collar shirts are Oxford weave
Fit Detail:Structured bodice for enhanced support & lace-up corset back
Descriptions SKU : GLY25W0020 Package Weight : 2000.00 Fabric : Silk Like Satin Length : Chapel Train Silhouette : Sheath/Column Neckline : Straight Straps Sleeves : Long Sleeves Back Style : Covered Button Body Size : General Boning : Yes Built In Bra : Yes Note:The dress does not include any accessories in the picture, such as wraps/jackets, gloves, veil, handbag, etc