Yes, Ezhavathy or Purohithan or Kavutheeya or Komaram are Bengali brahmin came through Andhra Pradesh and Tamil Nadu.
Their ancestors did yagna in Kerala and also they were traditional ayurveda teachers and priests in many temples.They brought 'Sakthi' worship in Kerala.They are Chaturvedi brahmin. Most of the male were known as 'Manthrikan' or 'Mantrikan'(those who expert in Manthram and 'Tantra' with divine power).

Perumal Vaidyars- Ezhavathy or Purohithan or Kavutheeya or Komaram were Kottaram(palace) vaidhyars in Sri Padmanabha Palace in Thiruvananthapuram. They are known as 'Perumal Vaidyars'.These Perumal Vaidhyars stay at 'Kallambalam' in Thiruvananthapuram district.

Ezhavathy may be ayurvedic vaidyars , but, they were non-veg comparing to Nambudiri.