Good luck with the steerer is all I can say. Probably ids Luck if it happens to turn up for a price you want. But Alu-O's where common so maybe not to bad (and 19" is also)
The frame is the same as mine, same 3rd batch (out of 4). i.e removable dropouts, riveted cable guides. I can double check the length but I', sure I'm right (no not big headed just I will have checked it many a times) and I keep a record of them in google docs, should I ever need it.
160mm is the length of gate frames. That's 10mm longer then a 20" Kona and they are a long long headtube.
P.S. size measurement is Centre of bottom bracket to very top of the seat tube if I remember right. Not centre or top of the top tube. Maybe you have a 21" (if they made one, i'll look at the pics
While you're at it though could you measure the rear drop out spacing (distance between the axle hole at the rear on the inside.) is it 130mm or 135mm ??