Arcane Ward: Target: Non-Magee Object
When this object is the target of an incantation or enchantment spell, you must reveal Arance Ward. That spell is countered (canceled without effect). Any mana spent to cast the spell is refunded to the caster. Then destroy Arcane Ward.
Teleport: Target: Creature & Zone
Target creature is Teleported to the target zone. [...]
Lesser Teleport: Target: Friendly Creature
Target Creature [...] is Teleported to target zone up to 1 zone away from its current zone.
So I find it obvious, that if a creature has an Arcane Ward both Teleport and Lesser Teleport will be countered.
If Arcane Ward is attached to a zone and regular Teleport targets that zone it should also be countered. But I am not sure if it also counteres Lesser Teleport, because the Zone is not listed in the targets. But in the text is says target zone.
So does the zone for Lesser Teleport has to be targeted regularly including stuff like needing line of sight form Caster (releveant for steep hill or walls)?