What is interesting for you is that school vertical is already included into ERPNext. Healthcare has been recently merged and NGO vertical project has been launched a few days ago.
ERPNext has website features with customer portal. Portal already includes things like issues, orders etc. You have the Web Form capacity, that is graphical composition of new form based on existing doctype. What seems to miss is multilingual and blocks drag & drop interface. It may be good additions to Frappé/ERPNext and if people are interested, bounties can be launched (the foundation has launched recently a bounty system).
FlectraHQ is branched over Odoo master and so Odoo v11, so it will be Python 3.5. Py3 will arrive on ERPNext too, but it is a little less urgent because of rolling release model (no need to support major version for multiple years, as Python 2 support will end on 2020). Flectra alpha will be released in October. We’ll see what is included and, even more, which governance and community will lead.
About ERPNext community : I’m very new but I also feel it very friendly and helpful. Frappé Tech seems to really follow open source spirit and that a major point on my view.