Tikki and Plagg would be very jealous. xD

The Secretarybird would manifest similar to how Champions of the Butterfly can, (though based on one's Passion rather can a need for help) so there can be a good variety of possible powers they could manifest, depending on what they focus on. A big difference between Secretarybird and Butterfly though is that Secretarybird doesn't change the holder's appearance, and powers manifested by the Butterfly tend to be more potent since there's two people involved.

Marinette: I could see the main power for her manifested through Zeal could be something related to sewing. Perhaps manifesting material and mentally guiding it with her mind; which could be used to to bind enemies, set traps, or perhaps catch people falling, etc. Other possibilities could be perhaps something related to baking, gaming, or drawing, though her main Passion would be more likely to manifest.

Flairr is a proud and flamboyant kwami, with an abundance of confidence. Not just for himself, but for all of those he interacts with as well. He is easily enamored with just the idea of possibilities of what one can do, and tends to drag in others without stopping to see what they might think. He is always extravagant with his actions, and tends to use nicknames more than actual names.

Flaair's Miraculous is golden chained rings, and his tool is a naginata. His favorite food is shrimp, and his transformation phrase is “Flairr, heart in!”.

I've had this ask for a while, and while I can't think of one for everyone, here's the ones I did come up with. (Adrien's and Marinette's are from a previous post but I'm including them here too.)

---

Marinette - I could see the main power for her manifested through Zeal could be something related to sewing. Perhaps manifesting material and mentally guiding it with her mind; which could be used to to bind enemies, set traps, or perhaps catch people falling, etc. Other possibilities could be perhaps something related to baking, gaming, or drawing, though her main Passion would be more likely to manifest.

Adrien - Adrien using the Secretarybird would actually be pretty interesting, because as seen in Wishmaker and throughout the series a lot of his goals and talents in life were chosen by his parents. So perhaps something related to fencing or piano could manifest for him (a power that gives him perfect swordsmanship, a power to make everyone move in time to his music, etc), but it’s likely these powers would be weaker for him as it’s not his own personal Passion. The strongest Zeal he could summon wouldn’t come around until he finds his own Passion in life.

Alya - Honestly, I think Alya's akumatized powers as Lady Wifi would work well for a power she could manifest with the Secretarybird. Being able to manipulate technology for reporting is very fitting manifestation of her Passion.

Max - Max would gain the power to connect to and use technology just through touch. Contact with one security camera would let him view and control the whole system. Tap any device connected online and he can access the internet with just a thought. A car would drive him to where he needs to go just as long as he maintains physical contact, etc.

Marc - To create a temporary fantasy world one can interact with, not one that can impact reality; but something more akin to a dream or a scene being played on stage, though it would feel realistic to those interacting with it. I think all parties involved would be aware that it's not real, so it wouldn't impact people's minds.

Lila - I think Lila would gain the ability to modify her appearance at will, to become the person she wants to be with just a thought. I'll be honest, I wish we knew more about Lila as a person to give her another power, but it seems that lying and manipulation is the only thing we really know she's passionate about.

Felix - You thought Felix was a good thief before? Well now he has powers to make it even better. He doesn't need to be near someone to nab something, but just have a target in sight in order to steal it without anyone noticing.