#2: I retired a long time ago (haven't served as a military IF for a long time)... am I eligible? YES, and the expiration date on your certificate will be 24 months after your date of application. Here is the applicable text from the Final Rule:

We agree that former U.S. Armed Forces instructor pilots should be allowed to apply for flight instructor certificates and ratings. Therefore, we have revised Sec. 61.73(g) to include both current and former U.S. military instructor pilots or former and current U.S. military pilot examiners may apply for and be issued a flight instructor certificate. We have not restricted this provision to just former military instructor pilots and former military examiners who have been separated from the military within the preceding 12 calendar months, because we have decided to extend this to all current and former U.S. military instructor pilots and military pilot examiners.

The new 61.73 words support that:

(g)Flight instructor certificate and ratings. A person who can show official U.S. military documentation of being a U.S. military instructor pilot or U.S. military pilot examiner, or a former instructor pilot or pilot examiner may apply for and be issued a flight instructor certificate with the appropriate ratings if that person:

(1) Holds a commercial or airline transport pilot certificate with the appropriate aircraft category and class rating, if a class rating is appropriate, for the flight instructor rating sought:

(2) Holds an instrument rating, or has instrument privileges, on the pilot certificate that is appropriate to the flight instructor rating sought, and

(3) Presents the following documents:

(i) A knowledge test report that shows the person passed a knowledge test on the aeronautical knowledge areas listed under §61.185(a) appropriate to the flight instructor rating sought and the knowledge test was passed within the preceding 24 calendar months prior to the month of application. If the U.S. military instructor pilot or pilot examiner already holds a flight instructor certificate, holding of a flight instructor certificate suffices for the knowledge test report.

(ii) An official U.S. Armed Forces record or order that shows the person is or was qualified as a U.S. Armed Forces military instructor pilot or pilot examiner for the flight instructor rating sought.

(iii) An official U.S. Armed Forces record or order that shows the person completed a U.S. Armed Forces' instructor pilot or pilot examiner training course and received an aircraft rating qualification as a military instructor pilot or pilot examiner that is appropriate to the flight instructor rating sought.

(iv) An official U.S. Armed Forces record or order that shows the person passed a U.S. Armed Forces instructor pilot or pilot examiner proficiency check in an aircraft as a military instructor pilot or pilot examiner that is appropriate to the flight instructor rating sought.

In addition, here are the directions contained in the FSIMS job guide (Volume 5, Chapter 2, Section 15) that address time limits:

"7)    There is no time limit on being a “current” or “former” U.S. military pilot, instructor pilot, or U.S. military pilot examiner in applying for and being issued a certificate under 61.73.