Mike, I said the helmet was in need if TLC - sadly the rest of the armour is really a DIY kit that really needs to transferring to the Intensive Care Ward.
Being serious, it is in fact very interesting. Towards the end of the 18th century there was a mood of nostalgia abroad for the glories of the past after some 150 years of enforced peace. The bushi began to take an interest in ancient armours and those with the money had copies made. At first they were wildly inaccurate, I suspect because the armourers had to work from paintings, but later when they had examined preserved examples, very good replicas were produced. The armour you illustrate incorporates some features of an o-yoroi but misses wildly in many respects. Most obviously wrong is the dou, which is a version of yokohagi okegawa dou, whereas a real o-yoroi would be in two pieces, a separate solid right side plate and a lamellar dou covering the front, left side and back. I am intrigued by the hinge that allows the upper part of the front to be swung down, I have a late Kaga dou with the same feature that I have never been able to explain unless it was for someone with a physical problem. The back of an o-yoroi had one row of scales laced in reverse to allow the shoulder straps to be swung back to make it easier to put on. The maker of this armour tried to incorporated this idea as well as adding the large ring for an agemaki bow that would form part of the shoulder guard attachments. The armour has been provided with o-sode (large shoulder guards) as an o-yoroi would have, but of false scales, kirritsuke kozane, rather than real scales. O-yoroi had four pendant kusazuri hanging from the lower edge of the dou at the front, back and sides. I think the piece shown on the right hand photo is either the front or back section, with three fastenings that correspond to loops on the dou front and back allowing it to be detached. You are right in that the piece next to this is the tare for the mask.
So what appears to be there are the remains of a very interesting armour that can be dated reasonably to sometime in the second half of the 18th century. There seems to be an o-sode, three sections of kusazuri and the shinguards missing.