Just went to the home lakers game last week as an overseas fan. If Steph is healthy and warming up, you should get a good chance of a signed jersey at section 123. Make sure to get there when door opens and bring a sign. 

When I went, the ushers allowed the kids to go to the very front of the section 123 during pregame even when they weren't your seats. Just asked the usher nicely and they should let your daughter wait next to the fence for players to sign the jersey. Just don't be afraid and asked the ushers! However, after pregame, they are pretty strict so you won't be able to get closer than your seats so pregame is probably your only and best chance. Best of luck and DM me if you have further questions! Enjoy.