Unfortunately, the flag variables discussed in the papers you linked to are not currently available through IPUMS-CPS. I have passed along your interest in these variables to the IPUMS-CPS team. I can’t say for sure when these variables will become available, but I know that IPUMS-CPS is always looking for input from researchers on what variables to integrate so I have no doubt that these will become available in the future.
In the mean time you can merge the variables from the NBER files onto the IPUMS-CPS files using the instructions found here: CPS has data available on multiple job holders. Where is the comparable variable in IPUMS' CPS?
I hope this helps.