I had a whole quiver of microfreaks for my kids a long while back and they are great. Not sure why I would get a 4.8 microfreak instead of just getting a superfreak, I guess is you had a real short wide kid maybe
I love my old style maui edition super freaks (full dacron no xply) so I expect you would like the kids version if you can get it. I know some foilers use kids sails as they want the real small sizes. But if I was going over 3.5 I would just go with the adult superfreaksas the mast cutout will be normally placed
Except for someone very short, I don't think kid sail are a good option : wishbone window may be to low.
For very small size (sub 3m) I use a sailwork, and there are some option (Goya, Horue... ).
What sail responce type do you seek with this sail ?
I'm about 6' and use the Pryde DragonFlys kids rigs in 2.5 & 3.5. Boom cutout isn't an issue, I add a little extra mast extension to get the boom a bit higher - still fits nicely in the cutout and I figure if I'm on the 2.5 I'm kidding myself to think I'm losing noticeable efficiency, way too much else going on.
Only concern will be long term durability, at my 90kg in big winds some of the wipeouts can be spectacular - interesting to see how they hold up over time. For now loving the super light materials and overall feel.
I think there a few brands making what I'd call "junior" wave sails (as opposed to kids rigs) that are a great option for foiling.