I was there this morning. got to the line by Suess by 7:30...we found out that they actually opened WWOHP for onsite guests at 7:15. We were inside by 7:45. They were being very strict about onsite key cards, and checked them a couple of times down the line. There was a separate line forming through the other side (Marvel) for offsite guests.
We got in, way less crowded by appearance but Olivanders already had a good 45 minute wait that early so forget it. Went to the other shops, I bought a wand from Dervish & Banges for my son and shirts for the girls that say "Pygmy PUffs, Peacefully Pet the Puffs" which they will love in Honeydukes which is such an adorable store. Dervish & Banges was PACKED and clausterphobic, and it wasn't even 8 AM. We saw the marketing team of Universal and talked to them for a while, we met the director at an event a couple of days ago, and they offered to get us Butterbeer but we were really just there to pick up a few things and get out so we declined...too sweet for that early since we hadn't eaten anything yet.
On our way out, we saw a cast member by the ropes in the center in between Suess and Marvel kind of yelling at a guy working a cart, because offsite guests were walking around the other side of his cart and going up the Suess way. I'm sure they probably got in, because past that they didn't check cards anymore. The cart guy said "how am I supposed to stop them?" and the rope guy looked mad and said "direct them over here, they have to go through the ropes!" So, they still don't have it quite together. Lucky offsite guests scored on that one, because the wait to get in climbed to two hours very quickly...at 11 we heard a guest over at the Studios where we were stating they had just waited two hours to get into the land itself.
Bottom line...if you want Olivanders without a freakishly long line, you have to get in line at like 6:30, no joke. There is no telling when they'll let onsite guests in; today it was 7:15. Dervish & Banges and Honeydukes did not have lines.
Hope this helps!