1-how many addresses are there with this characteristic?
I took a look at all p2ph addresses (so the one starting with a '1'. I found over 1.5 million addresses with the characteristics you described which have been funded at least once:
1AAaaCnWptsdikfLwQKpPAkVvGWwXmcTwH
1AAAakfPsjEpmfMBFzaQHeoGTNDUttSYHB
1AAaALjAYkZxeZfGfGbMowNFgjPgqmjept
1AAaaNhHmHbZvzUzwzwhmeUXviaTAMqDXM
1AAaAqCudRbWniNHeRejejEZszisfELBEd
......
<snip 1.5+ million addresses>
.....
1QLZXYbzXPxpenwCYsbccudSSrHKhKmSnf
1QLZYeftHVptyyjjDVZwfsLvJamRkMhsoS
1QLZyPXavHLGMNZRZWEVcBWjRVRvPeLiGb
1QLZywqbiQobZMpWNPXthyYJtNgfcLRRSV
1QLZzaiyVLvZUfimDNwfJNRxPQMJoLmhbb
1QLZZFCFTZqnnZEorbSjFvbpQefgSpBijg
1QLZZpbdeXkbBSizdymoiPxUxPtHQsCmaW
So the same conclusion as I had generating random addresses: they are not that special!