I followed the Google Docs link you provided -- thank you, that was very helpful.
My reply will repeat your questions:
1Q. Do I braille KEYS at the bottom of print pages, with exercise instructions, and with exercises. These KEYS are a reference to the material its printed close to, or to the print page it is at the bottom of.
1A. The keys are for the teacher or parent (obviously). If you are brailling the student copy, it is my opinion that you should ignore the keys. However, California may stipulate that you retain them. You need to ask the person who assigned this work to you to see if their inclusion is required. I surely hope not as they will take up so much room and the student need not read them. (If they are required, you can single space the key information.) Same advice for the "At Home" and "En Casa" information. I hope you are allowed to omit those. If required, I would ask if you could make a separate volume showing only those items, listed by page number. If no mathematical expressions are included in these teacher/parent notes, I don't see why you can't braille the separate volume in literary code.
2Q. Do I use the General Omission symbol for blank spaces for answers.
2A. Yes. Follow Nemeth omission rules (if print shows a line, you braille a long dash; if print shows nothing, braille the General Omission symbol).
3Q. Can I use the shape indicator for blank squares and circles for answers; also some of the KEY numbers are in an ellipse (oval).
3A. Do not use the shape indicator in the early grades. See 220.127.116.11 in the new "Guidelines and Standards for Tactile Graphics." (link is given below)
4Q. Can I use the multi-purpose symbol following a decimal point (e.g. 2.a).
4A. Yes. Follow Nemeth rules.
5Q. Can I use the boldface and italic typeface indicators.
5A. Page 4 of Promising Practices (see link below) discusses this. If you feel it is necessary to include emphasis, follow Nemeth Code rules, but DO list the symbols on the Special Symbols page.
6Q. Can I use print page numbers CS1, ...; B1. ...; KSH1....
6A. Sorry, I don't know what you mean. Follow print for page numbering. On the page corners, use Literary code; in the body of text, use Nemeth code.
7Q. Do I move Table of Contents prior to brailling the pages mentioned, CS, KSH, and B.
7A. Sorry, I don't know what you mean.
There are many fine guidelines in the new tactile graphics guidelines document posted on the web at http://www.brailleauthority.org/tg/web-manual/index.html
Unit 11 discusses graphics for early grades. Unit 6 discusses math and includes information on early grades.
I also suggest studying Promising Practices, an APH publication, for more ideas and advice. http://www.aph.org/atic/practices.html
Note that you need to show the graphics and words associated with each page number. See BANA Update pages F7-F8.
Early grade math books take a lot of time to braille. Many graphics are needed, as well as a large dose of creative thinking. Good luck!