agree with your opinion on building. i have built and crashed two previous balsa models long ago. love everything about building balsa, and flying balsa. hate crashing balsa, and that's what beginners do.

just my opinion, but reading the o/p, it is hard to detect whether flying or building is a priority. since they only mention building, perhaps they have no intention of flying. it would then fall to what type of construction materials and why, certainly in that scenario, foam doesn't make a whole lot of sense.
since they checked out in july, we may never know.