Hey there,
FAR reg 61.183 seems to cover it I think. You can view the FARs at
www.landings.com , but in short yes you will need an FAA CPL SEL and Instrument rating.
There are two written exams FOI and CFI. Then an oral and flight test.
You will be able to instruct PPL and CPL single.
If you want to teach Instrument you will need to do the written for the CFII and take CFII flight test.
For the MEI just a flight test.
-273
Sorry about previous comments snapped my ankle over the weekend so been out of it on pain killers.