Do I need to add money to keep my gophone account active to port my number after my balance expires?

When you port a number you are moving it to one service provider to another. With gophones the Sim in your old "dumb phone" can be placed in the new phone directly if the same card type is used in the new phone. If the simcard in the new phone is diffrent you would contact customer service/ Tech support and have them do a device swap. Either way their is no reason to open a new account to change devices.

If your husband gets a new phone see if your sim fits in his old one if so you are golden. If the card does not fit customer service can send a compatable card. remember keep your account charged and active during this.

A dumb phone SIM card is not provisioned for a smartphone.  She will need a new SIM card.

Seitching from basic plan to smartphone doesn't require porting your number.

Porting your number is if you are changing carriers.

If you are staying with Gophone, just change your plan to include a plan with data ($45 or $60 plan).  Changing plans will replace your current plan and ATT does not refund, so wait as long as possible.  

You do not need to change your plan right away, you can add a $5 data plan to your dumb phone plan.  

No, I am changing providers as well.