I will try to help with general time-frames and face masks...
Yellow DS Helmet:
You pegged it.... Late '60s - early '70s. Cool/unusual face mask. Does it have an inner suspension system, or a padded interior? (I'm guessing it's a suspension helmet).
White Leather Helmet:
Mid 1940s. It's the oldest one you have pictured. Might've had a face mask similar to this...
https://www.ebay.com/itm/25503094223...AAAOSw7iFg16aI
Yellow and Black Wing-front Helmet:
Mid-late 1940s. Never had a face mask.
White Shell/Blue Wing-front McGregor Helmet:
Early 1950s. Never had face mask.
Red Shell/Tan Stripes Globe Helmet:
Late 1940s. Never had a face mask.
White Shell Helmet:
Late 1950s - early '60s. Most of these were worn with face masks, but yours was apparently never fitted for one.
Yellow Shell Helmet:
Late 1950s - early '60s. This one (much like the white one) had a mask attached, a tiny portion of which is still visible.
Blue Helmet with White striping:
Cheaper- possible Youth "Play Helmet", circa early 1960s. Probably never had a mask.
Tan Helmet with White Stripe:
Early-mid 1950s. Never had a face mask.
Tan Helmet with Black stripes:
Late 1950s Helmet with nifty black Single-bar Mask
Hope this is helpful.