From Pokémon Platinum onward, if they are held by either parent in the
Pokémon Day Care, that parent passes down its IV in that respective
stat; HP for Power Weight, Attack for Power Bracer, and so on.
Now if your Sigilyph has 30 Speed IVs and holds the Power Anklet, the first baby will have 30 Speed IVs and it should have Hypnosis as that is one Pidove's egg moves.
Now, if you give a Sigilyph with 30 attack IVs the Power Bracer and you give the first baby, who has 30 Speed IVs, the Power Anklet, the baby will have both 30 Attack and Speed IVs and it should have Hypnosis because its an egg move of Pidove.
Question 1: Yes.
Question 2: It should.