Can you realistically be a CFI with an add-on rating?
 

Most places will offer a CPL(H) add-on rating requiring 50 hours helicopter, and from there it's possible to get a CFI add-on as well. There are plenty of non-Robinson options - Enstrom, Bell 47, G2, Schweizer/Hughes etc - but will any school actually hire a CFI with only 60 hours helicopter time, or is it all in the hands of insurance companies?

If the Licensing Authority certifies the Licenses and Operation.....and those wishing to build hours will work for peanuts.....odds are that could result in a job offer.

Would you want to spend your money with such an Operator....that is an individual choice one has to make.