Wadanohara, Froze, Rieta, and Etihw reacting to their pretty stoic SO getting amnesia and being much more energetic and cheery?
( Coming right up! )
FUNAMUSEA
WADANOHARA
She's super happy for you! She never knew this side of you existed, so she's happy that she gets to see it. She loves you no matter how you are, but she especially loves how happy you seem to be. She wonders if you'll get your memory back at some point and what you'll be like if it does, but she's just as willing to accept you if you go back to being stoic. As mentioned before, she loves you for who you are, no matter who that ends up being.
FROZE
She is... surprised to say the least. Not in a bad way, of course, she just didn't expect such a change from you. She's used to this sort of personality, however, and she doesn't exactly mind in the slightest. Sometimes she scolds you when you act too hyper, telling you that you're "just too much", but of course she doesn't mean it seriously. She actually likes seeing you so outwardly happy, but she won't come out and just say that out loud unless the moment is totally right.
RIETA
She's usually smiling when she sees you like this, telling you that she's grateful to see you so energetic for once. Not that she didn't like the way you were before - of course she loves you no matter what, undyingly loyal - but she certainly seems to enjoy this side of you in a way she hasn't before. She's constantly encouraging you to do things with that energy, saying that you should make the most out of it and really immerse yourself in the new mood that's come to you so suddenly. She'd like to see more of this.
ETIHW
They're playfully sad that they can't tease you anymore, but otherwise happy that they can see you so excited now. They offer to try to change this for you if you want - to help you get your memory back with their magic. It's entirely up to you, though. They like you both ways, but they especially liked being able to tease you when you were more stoic. That isn't to say that they wish you would go back to the way you were before you lost your memory, oh no, but they'd definitely be down to cast a spell or two if you wanted.