Taking the lead as well would automatically make you a target on some other Survivors. The tribe needed challenge strength so the tribe swap wasn't actually so hard for her as for others. Also having challenges that aren't just about a team but about an individual or two people teaming together definitely helps her make an impression. Concerning the later individual immunities I've no idea how good she is at balancing though she has concentration. It's a normal strategy of wanting to go with other strong people so the target isn't on her as much. But some of these strong people are also quite boring, so I don't want them dominating too much.
Lydia is probably really good at anything requiring balance. The only things she possibly does not excel at at I could think of is perhaps swimming though what could most likely be her downfall if she has one..puzzles or throwing accuracy I hope Im wrong but I see treacherous boring allies blindsiding her late in the game if and when she stumbles ( Mat/Commando).