Googled and found this list of Meghan's core friendship group. Everyone on the list attended the wedding.
If LondonWolf wants us to believe that assertion that Meghan has vanished "everyone" she knew with pre-Harry then she needs to prove that Meghan is no longer friends with any of the people on this list, otherwise unfortunately it does rather prove that LondonWolf is making up porkies.
*Benita Litt (MM's best friend since college, MM is godmother to her kids, she sat next to Doria at the wedding, and her two daughters were H&M's bridesmaids)
*Genevieve Hillis (friends since college, she co-hosted MM's baby shower)
*Lindsay Roth (friends since college, they "met in a Toni Morrison literature class")
*Daniel Martin (a makeup arist who met Meghan in 2008 when she was a struggling actress, he did her makeup for the wedding)
*Heather Dorak (friends since she was first a struggling actress in LA)
*Abigail Spencer (met at an audition when they were both starting out as struggling actresses. They later worked on Suits together but they were friends before that)
*Janina Gavankar (friends for more than "fifteen years" per MM's old instagram posts, they met when they were both struggling actresses)
*Serena Williams (friends for 12 years, met at a charity benefit, she co-hosted the baby shower)
Of course the list doesn't include the cast and crew of Suits, who she appears to still be on good terms with and many of whom have publicly defended and praised her on Twitter or in the press, or her longtime acting agent.