Janome all the way ... I consider that Janome make better sewing machines and Brother make better Embroidery machines.
Also not having adjustable foot pressure is a complete No No ... (and that was why I didnt like the Janome 4000 .. I traded up from it within a couple of months)
Looking at the specs
on this site I cant see any mention of an extension table .. Is some other retailor offering it as an incentive?
If so are they throwing in the full quilting kit, which include the dedicated feet and all important Walking Foot.
The walking foot will be the most important quilting foot to have and is pricey (@£49 last time I looked) so something to bear in mind.
I must say your daughter is a very patient girl ... A lot of youngsters seem to want things Now Now now ... but you've done a lot of research ... which will of course pay dividends.
Regarding the expense of quilting sets/feet/accessories ... Maybe just start her off with general sewing and see how she gets on with it and which direction she takes ... graduating to quilting naturally so its not one Huge expense all at once .. maybe for next birthday or Christmas present.
My first quilting set was a birthday present from my then husband and I at 50 years old was thrilled with it! it made piecing and quilting soooo much easier