Semantically, "Non-haven" by its very nature refers to a Haven, else there would be nothing to non-. Non- cannot exist in a vacuum, it requires a reference.
To labor the point, since it seems to be necessary:
When the rules and cards refer to a Wizard, they apply to your Fallen-wizard.
If we accept the above logic of non-, then
A Lie In Your Eyes And Eighteen Billion Other Cards wrote:Playable on an untapped non‐Ringwraith, non‐Wizard character.
You could play such cards on a Fallen Wizard because they refer to non-Wizards, not Wizards. It's untenable. There is no realm of possibility that ICE ever intended Malady to be playable on your Fallen Wizard. Or for Abductor to discard Fallen Wizards. Or Call of Home. Even Never Refuse would suddenly start applying to Fallen Wizard cards.
It doesn't wash. Panoply can be played at Hero Rivendell by FWs because it's a non-site card that refers to a Haven. Such a reference becomes to a Wizardhaven. Just as references to Wizards become references to Fallen Wizards where necessary.
The game is flawed, but this does not mean it cannot be loved.