It is a matter of persistence and consistency. As soon as she get's too excited - stop playing or doing whatever it was you were doing. Ignore her, if she doesn't calm - then it's time out zone.
She wants to be having fun and to be with you all. She will soon learn that "naughty" behaviour gets her put away from you so it will work. It just takes patience.
It's hard but try not to get yourself in a battle of wills. She will win if you do that. The only battle is for her to realise that you and your family call the shots.
I don't know if you do any rough or exciting play with Bella - but don't. This is too much for them and sends out mixed messages. Keep everything calm and steady. Have a specific toy or place - better outside, where she can run and get excited. Inddors, try tiring her out with mental exercise - basic command work, sit, stay etc etc.
Commands is another important area - they must be used to mean the same thing. If you use "down" when she's sitting to make her lie down, then you can't use it to for getting off the sofa etc - she will be confused and not know what down means. You might want to use "off" to get her off the sofa and while saying it - pick her up swiflty and firmly and put her on the floor.
Either way - a firm NO should always mean the same thing - ie stop that.
This is a tough time and will seem never-ending - and some of it will never end coz that's what makes Cockers
But the bolshy infuriating puppy stage will end. How soon though is largely down to yourselves.
Everyone must treat Bella exactly the same - no exceptions and you will get through this.
Chin up - keep at it.