You can only make calls to other Nigerian Networks for now

You need internet connection to initiate calls, however the Wificall app has very minimal data consumption

Yes it is unlimited, which a fair usage policy also applies. See terms of service

You can always switch to any plan of your choice after.

The Wificall service can be used with an IP phone.

A number will be assigned once payment is made.

Yes you can, the can be gotten on https://myaccount.wificall.ng/#/login

0201229xxx format

Yes, email and phone number verification are essential in signing up for Wificall, hence, you would need to create another account for Wificall.

Yes, you can create conference when you are on the business plan.

This is because the microphone permission on your mobile device hasn't been granted. Navigate to the settings on your device and allow all permissions for the Wificall app including the microphone permission.