I have faced this exact problem with Canadian govt forms.
Evince doesn't support them. They are so specific about only adobe acrobat to fill out the forms.
I can open them in firefox but can't update them properly
The only option is to use my barely hanging on 10-yr old windows machine.
Let's hope that eventually they move on to a simpler web form.
Let's hope that eventually they move on to a simpler web form.