Yet
Return from the Different Dimension is no longer on the field when it removes the summoned monsters from play again and Wildheart ignores that effect. To me this is pretty clear. Monsters such as Horus LV6, Legendary Fisherman (with Umi),
Silent Swordsman LV5 and any non-effect with
Non-Spellcasting Area all have immunity to spells. I believe that the
Swords of Revealing Light rulings clearly show that monsters that can ignore the "you can't attack" effect grant the controller the ability to attack even if it is the controller and not the monster that were being prevented from attacking.
Now the exception to this is of course the
Non-Spellcasting Area vs.
Inferno Fire Blast ruling. The reason this is different is due to a targeted effect resolving and leaving a condition on the
Red-Eyes B. Dragon. So when
Non-Spellcasting Area is later activated it will confer immunity to Spells from that point forward but it does not have the ability to negate the condition which was already applied. This differs from the effect of
Burst Stream of Destruction which leaves a residual field effect preventing any
Blue-Eyes White Dragon from attacking this round which of course
Non-Spellcasting Area can bypass and allow your Blue-Eyes to attack.
I see
Threatening Roar as the same type of effect. A residual field effect which Wildheart will ignore and be able to declare an attack anyway. Of course our closest card to
Feather Shot is
Diffusion Wave-Motion that conveniently does not address the issue of immune monsters being able to still attack in the rulings. Definitely something I think should be asked on the list but I would be truly surprised if it doesn't come back the same as the Swords vs. Horus ruling.
Feather Shot is a field effect preventing other monsters from attacking, the immune to spells monsters should certainly be able to attack anyway.