Pictures 1 & 2 :
Chainmal helmet with face mask - NorthWestern Indian, probably Rajput or Sind (if the bird topping the helmet is original it is the Kutch Bhuj area (today`s Pakistan, which I am more and more certain the longer I examine the copper/brass craftsmanship so much in Lahore style) made in Mughal fashion. The mask was used by full clad armored cavalrymen , specialy mounted escorts, paiges and retainers.
The helmets inspired by the burkha ( Islamic female veil) are named purdah or purdha. We all know how hard is to accuratelly date Indo-Persian archeological finds due to their extensively long mentained and unchanged style which leaves us at the mercy of apreciating age based on general health and condition of the piece itself which is almost an unsafe thing to base a verdict upon but I take my chance and say 19th century, even though next person that has a solid argument I might not know can make me look like a complete fool in regards to age , however as far as origins and the rest I stand firmly by my affirmations ...
After comming back from work I would be happy to comment on the rest of your stuff ...