IMO - Theo got to CC and was comfortable at that stage because he was sending personal messages and watched you tube! The question is what happened between the last message until the phone woke up at 6 am, 4 hours of silence. IMO - if the phone, slept, woke up and pinged in the same location it is a good indication why the sand should be dug up!
IMO - Theo left CM comfortably because he never argued why he was asked to leave, he left his drink on the table rather then take it with him to the bathroom and he was also talking to an unknown male and ignoring advances from girls so it appears to have been a very serious conversation.
IMO - KOTOE9021 from I/gram took a picture at sunrise at Tallows Beach on the same morning Theo was missing on the 01/06/2019 as the sun was rising and that was the very last post she did on I/Gram. She replied on the day saying thank you to everyones comments but after this day did not reply thank you to a comment and has not posted anything since the 1st! IMO there is a very strong possibility she is also missing.
IMO Theo was not asked to leave as such he was asked to go somewhere at the end of Tennysons to meet someone who then went together to CC. The end of Tennysons is of course the homeless campers.