Always talk to your doctor for specific advice regarding your own medical case as they will have better understanding of your context. I see no concerns for your wife getting the vaccine from what you have stated and she is likely in a higher risk category that would be prioritized for the vaccine.
Specific data on individual drug interactions is not available yet. Here are the drug monographs in Canada for the Moderna and Pfizer vaccines from the companies. I didn’t see any concerns except for the note from both that immune suppressed patients may not mount as strong a response to the vaccine. The treatments she is on now should not cause overall immune suppression but your doctor is best positioned to answer this.
https://www.pfizer.ca/sites/default...h_COVID-19_Vaccine_PM_EN_244906_09Dec2020.pdf
https://covid-vaccine.canada.ca/info/pdf/moderna-covid-19-vaccine-pm1.pdf
From a mechanistic perspective, Letrazole and Ibrance should not interfere with how the mRNA vaccines work since they target specific hormone receptors and not general DNA/RNA function like traditional chemo.
Radiation targets a specific area so it will not make the vaccine ineffective which will be all over the body. And the vaccine already would have taken action and degraded before she had her next round unless you did them the same day.
The main risk might be things like potential increase in nausea, fatigue or aches if she already gets those from her other treatments.