1. These are often termed old-style numerals. Nothing new under the sun here. If anything, all fixed height numerals are the newer invention. (conjecture, feel free to research this and refute, but I'd bet it's the case)
2. Research into how we read whole words indicates that letter height and the profile of entire words is critical to faster reading. SAME HEIGHT WORDS slow us down. The changes in word outline can help us along. 2009 2oo9. A poor example given that I'm simulating old-style numerals, but you get the idea. In blocks of text, not in tabular formatting, the changes in the numeral heights can help carry the eye along.
Key takeaway (here): Yes, tons of research shows that people read lowercased words faster than they read uppercased words. It also shows that the difference disappears with practice -- turns out lowercase is more common 'in the wild'.
I doubt it, given that all-uppercase is the older style.
http://en.wikipedia.org/wiki/Letter_case#History seems to agree:
"Originally alphabets were written entirely in capital letters, spaced between well-defined upper and lower bounds"
But feel free to research and refute.