Fundraiser - how to tune settings


I would like to know how to tune the Fundraiser plugin settings in order to:
- Change the wording displayed (even if in Settings I have replaced "Pledge" with other wordings, in the checkout page it still displays "Pledge" --> please see text at )
- Remove the "None" option for the pledge / purchase (same example, )
- Enable the user to purchase 2 or more Rewards ("Packages" in my wording) on the same transaction
- Enable a check in the address field at checkout to make sure I accept pledges/purchases only from people in selected countries (or a single country)

I understand that some point may be beyond the current extent of Fundraiser plugin, just willing to explore what I can do for my current project!

Thanks in advance!