I think hiking boots (given they have hard toes) are OK for sometime. I ride in cheap rubber boots when it's too wet. If you have TSC nearby they have number of different boots so you can try before you buy (like this one: Ariat Ladies' Fatbaby Boot, Brown Bomber - 707933599 | Tractor Supply Company ).
As for helmets I know of 3, which looks "Western" (but you really want to try before you buy or buy from some place you can exchange, sometime it's hard to find a helmet that fits your head): Dover Saddlery | Troxel Sierra Riding Helmet. and Browsing Store - Troxel Cheyenne Rowdy Western Helmet and TROXEL Dakota Duratec Western Helmet Helmets Protective Equipment Western HorseLoverZ.com )