Contacts, help Android

Say, we have the following phone, Vodacom Smart 6 (very entry level Vodaphone), and battling with managing the contacts on the phone. There is a Gmail account that's active on the phone and numerous contacts from this Gmail account are available on the phone.

1. I understand that all the contacts are stored under 'people'? There seems to be 2 places to store them, either on the phone or in the Gmail account. I would like to store all of them in the Gmail account and make this the optional or the default option. How can I do this?

2. I have added a contact and find it under people but it's not available under Whatsapp. I can't find it in the whatsapp and I also don't now how to edit this contact. Kindly help us out as this is so confusing.

3. we are using the phone in Basic mode and limiting the number of icons available for ease of use. What is the easiest and quickest way to get the contacts?

4. I also wish to share a contact with a whatsapp recipient. Please explain the steps on how to do this.

Thanks