1. For someone to contact OP/RS via Wi-Fi you are talking about an internet originated connection (e.g. Facetime, which we know OP uses, Skype, WhatsApp etc). This could be received over their phone or iPad (exclude WhatsApp) as a data connection in which case there would be no record of the communication as it's not a 'phone call'. Some applications allow you to communicate from the internet to a person's phone number - this would show up as an incoming 'phone call'. We have all the phone calls only.
2. Moller tells us that the times shown on the WhatsApp messages are out by 2 hours (they're a Universal time, not South African time) so we've adjusted accordingly. The phone records are local South African time, so no adjustment needed.
Be careful looking back at tweets - the time shown is your local time, not the time in the country of origin. So Reeva's tweets in Feb 13 are out by 2 hours to the UK at the moment (this will change shortly when we move our clocks by an hour).
BBM - Ohhh... that explains so much !! And unlike the other explanation I had seen, yours makes all the sense in the world. Thank you, that's a big help.
P.S. In the beginning the Tweet time thingy was confusing to me also, but on that one, I was able to figure it out on my own.