John Weasley?

[hermowninny719]

No: HPFGUIDX 86858

As I am fairly new at obsessing about the Potterverse, I was reading 
some old interviews with JKR the other evening.  I found the 
following Q & A in a online chat at scholastic.com (February 
3,2000)...

Q.  Do you take real people you know and put them in your books? 
A.  The closest I've come to putting a real person in my books is 
with Gilderoy Lockhart, who is an exaggeration of someone I once 
knew. John Weasley is a little bit like my oldest friend, a man I 
was at school with, whose name is Sean. But neither of them are 
accurate portraits. 

Who is John Weasley?  Could JKR have possibly changed the name of a 
character at this point (after PoA)?  Could John be the missing 
Weasley and JKR just slipped in giving his name?  Any other thoughts?

I have searched the archives and "Fantastic Posts" and haven't found 
where this has been discussed before.  If it has, please direct me.

-Hermowninny