My my - lots of questions!!  Let's see if we can help answer a few.

First, chemical straightening or the use of heat to straighten hair will damamge it.  Chemical processes open the hair cuticle which weakens it.  Heat removes the moisture which leaves it brittle.  Both can/will cause breakage.  You can try to minimize the damage by moisturizing and deep conditioning your hair ALOT.  The olive oil is a good treatment for your type of hair.  Keep doing that.

I don't have any suggestions for straightening your hair, but maybe someone else here can help you more on that topic.  

If you must comb your hair when wet or in the shower, I highly recommend using a wide toothed comb.  Make sure the comb does not have any ridges on it that might scrape and damage your hair more.  Most commercial combs have a "seam" on each tooth.  This seam can do serious damage to hair.  You can use an emery board/cloth to sand that ridge down, or look to purchase a comb that does not have the ridges.

To reduce frizzies you should minimize the amount of combing/brushing you do to your hair.  There are products out there that can also help reduce the frizzies.  One of our curly headed experts will probably fill you in on what works for them.  

Hair usually grows at an average of 1/2 inch per month.  Growing long hair takes a lot of patience and care of the hair.  Good health is also important for hair growth.  If you are anemic, you should work on changing that.  Take your vitamins, eat healthy foods.  Your hair is an indicator of your overal health.  A healthy body will result in healthy hair.

Lemon juice can lighten your hair, but it also dries the hair out.  If you do use it, be sure to condition/moisturize to prevent more breakage.

I hope this helps answer some of your questions.  Feel free to ask more!