1. In regards to your question of whether to note Hispanic or Chicano--I think it would depend on the school you're applying to. Check out the ethnic data on LSAC for each school you apply to. See which ethnic group is less represented and go with that one. The distinction shouldn't matter much though. If you're applying to schools in California, definitely put "Hispanic."
2. In regards to re-taking the LSAT, if you've taken proctored tests and have scored at 167 or higher it seems reasonable of an expectation to score higher if taken again. But keep in mind that scoring 168 or 169 isn't going to make a huge impact, so really it comes down to if you're confident that you'll do so much better that you can crack 170--in which case you should retake it. Also, if a school is on the fence as to whether or not to accept you, and aside from your LSAT score you are a good candidate for them, sometimes they will actually contact you and ask you to re-take the test (the Feb. test). It's rare, but it happened to me.
3. I would say to get those applications out sooner than that. I cannot overstate the importance of applying early. Why is it taking you so long? Remember that you can submit your application and then send letters of recommendation and updated LSAT or updated GPA information subsequently. All you really need to send right now is your application form, personal statement (and diversity statement!), and your resume. Trust me, the early the better. If you're having problems with your PS, DS, or resume message me and I will help you with it.