Can I cast hold person, and have my Hound of Ill Omen attack, on the turn I summon the hound if our initiatives match?

If my Shadow Sorcerer survives to level 6, I will have a Hound of Ill Omen.

As a Bonus Action, you can spend 3 Sorcery Points to magically summon a hound of ill omen to target one creature you can see within 120 feet of you.
{snip stats and moving through objects and creatures}
The hound appears in an unoccupied space of your choice within 30 feet of the target.

I will summon it next to the target for the purposes of this question. (within 5′)

Roll Initiative for the hound.

For this question, the Hound’s initiative roll ends up being the same as mine.

Additionally, while the hound is within 5 feet of the target, the target has disadvantage on Saving Throws against any spell you cast.

Here is where the order of operation concern comes in.

  1. I have used a bonus action to summon the Hound

  2. I can use an Action to cast a spell: I specifically want to cast Hold Person.

  3. The Hound can attack on its turn (when I summon it)

    It is my understanding that the target will have disadvantage on the saving throw versus Hold Person. If the target fails its save, the Hound will be able to attack the held target with advantage, and will have an automatic critical on any hit.

Is there a problem with this order of operations? The bonus action should be usable by me before I cast that spell, and summoning the Hound does not appear to be a ‘cast a spell’ action.

On the rare occasion that our initiative aligns, I’d like to take full advantage of it.

Will this work?