How do you think the other beasts might act if they had Tako forms?
Taking that they all can't detach their own heads on their own (per my knowledge) let's say they can now because Shadow Milk pranked them. They all be shocked at first yes, but once they realize it's harmless they will deal with it or find its uses until it wears out.
Eternal Sugar wouldn't have much use of this form on its own because she already makes other cookies or sugar angels do her chores.
If she is as lazy as I think she is, she will probably lose or leave her head around and don't even bother to pick it up because, well, getting that weight off your shoulders once in a while should feel nice. She will end up waiting to be picked up by someone, specially by you... maybe losing her head around is not that accidental as it looks...
She is gonna use her new "condition" to look helpless and try to gain sympathy from you being like "oh please, please! wouldn't you lend me your help, my dear? I have been so cruelly cursed and now I'm a defenseless cookie. I really need you my sweet, please, carry me and hold me close~~" so you would carry her everywhere.
Once you pick her up she will behave like a spoiled princess, asking you oh so sweetly to do everything for her: carry her around, brush her hair, feed her, pamper her... just... don't put her down and leave her behind, not even for a moment, or she is gonna have nasty meltdown. She is your curse to carry now.
Like everyone else, she can walk with her hair but because hers is that curly she wouldn't walk, she would "jump" around using her hair as springs... but she won't get far, it will exhaust her quickly.
Also, imagine poor Pavlova seeing Eternal Sugar's head on the floor getting his hopes up thinking that the beast has been slain and... nope, no, she is just there, sleeping and still very much alive. Poor dude.
Mystic Flour... what can I say? She wouldn't care much, honestly. Meditate with or without her head would be the same. Spreading the pale plague with or without her head would be the same, maybe even faster if there are two sources.
I don't know why but I think she would have a bit of a hard time, even if she says she is fine and doesn't care. Maybe she would have trouble reattaching her head, maybe she would leave her head somewhere in the pagoda and her body can't find it... all in all, she will need some occasional help from Cloud Haetae or from you.
She would be very grateful to you and Cloud Haetae when any of you help her return her head to her body. She really would try to not be a burden but... if you are the one carrying her she wouldn't be able to help herself but feel... joy... and silently wishing that you could keep holding her for a little bit longer but she won't admit it.
So, sometimes, when you are carrying her head and trying to bring it to her body she would try to guide remotely and hide her body away from you, extending that little stroll you both are taking together a little longer.
Even if you catch on what she is trying to do, from time to time just play along alright? let her be a little bit selfish and childish sometimes, I think she needs it.
About her walking style while in tako form... err... god, this gonna sound cursed... she would stand on her two tassels and walk like normal. If she lets her hair down she would walk, of course, like a spider.
Burning Spice is gonna take this as a challenge! How much carnage and destruction he could bring to these lands using just his head, he will wonder excitedly.
He will get the hang of it pretty quickly and I'm sure he will find its advantages for battle, like: grapple fleeing enemies with his teeth and bring them closer to his body using his hair as rope, do a one-cookie pincer movement, use his head as some kind of flail, throw his head at enemies so it gets tangled on their legs and slow them down...
Basically, he would behave the same, even with you. He would still demand you to spar with him, would still be your secret guard dog, would still boldly ask you to tend to his hair when he wants to relax for once... the only difference it's that he is now just a head... his body would still be spreading devastation or hunting some poor soul down witches know where, so efficient!
However, in that form, he would now also ask you very enthusiastically to use him as a weapon. Use his head in any way you see fit, be rough, be messy, whatever, as long as he is helping you eviscerate your enemies he would be overjoyed. He would encourage you more and more as the battle progress to be more reckless with him: "Come on! I will show them our power! I will prove my might to you once more! Throw me at them with all your strength! Hahahaha!" as if he was an overly excited grenade.
As only a head, he could walk with hair but I guess he would prefer to roll around like some devastating black ball full of thorns, smashing and wrecking everything that stands on his way.
Silent Salt... who said they don't have some kind of tako form already? I say this because sometimes I headcanon that Silent Salt is a hollow possessed armor entity. All will be exactly the same if that were the case.
Because of I'm writing this when they have not been released yet I don't know what they usually do or behave after they have been released from their confinement. Despite that, I believe they would be your knight in ebony armor, protecting and following you closely whether you like it or not.
Perhaps, after seeing their beast companions in their new state, they would get new ideas about how they could shield you from danger, for example, wearing their helmet.
What better way there is to safeguard you than literally wrap you with themselves? Maybe wear the rest of them while at it, nothing will stand between you and them that way. They would have never guessed that this complete and intimate act of your preservation would feel so... fulfilling... at the price of your freedom. Yeah, because ,basically, you would be wearing some kind Fallout's power armor but you are not the one piloting it.
Regarding how their head/helmet would get around maybe they could shape their ponytail like a hand and crawl around like The Thing from Adams Family. Another alternative, since they are possessed armor, maybe all their armor parts can split up and float around just like how it's shown in this youtube video about dark souls.
