For each of the fields that you like to have default value displayed and get cleaned on entry you can have following JS script in "enter" event....
if (this.rawValue == "<default value for that particular field>") {
this.rawValue = ""
}
and for "exit" event....
if (this.isNull) {
this.rawValue = "<default value for that particular field>"
}
Hope tha helps with the first issue....
And with the second question you had....yes it is some thing that can be done with few tricks and little script.
Your button does not need to be part of that subform...and noting wrong even if it is.
instanceManager.addInstance(true) //true is part of syntax however following example can give you better idea
_secondPageSubForm.addInstance(true) is what you would use in "click" event of the button where "secondPageSubForm" is your subform name to repeat and designed to fit entire page so you can continue adding entire page rather than part of page. And "_" (Underscore) is part of the syntax to recognize the repeating subform.
And to whole thing work as expected you need to save/render PDF as Dynamic template and set your "secondPageSubForm" as repeating in "Binding" tab.
Hope that helps, Good Luck,