score:4
- Is there a problem to cross the US border through LAX (holding a B1/B2 visa and 2 times, one on my way to BKK and another when going back to LIM) just to take another flight?
All things being equal you should be fine
- If there's no problem with the first question then I would like to know if the times between each flight that I am planning to book are enough.
More than enough time, even factoring in a couple hours of delay and crossing security and changing terminals. You have minimum 6+ hours. The link provides a walk-through changing terminals in LAX.