I have read in many places about Cula Sotapanna or 'Lesser Sotapanna' and 'Faith Follower'. Are they the same or different? Do both of them attain to Sotapatti phala in the same lifetime?
Definition of Faith follower and the timing of his attaining of stream-entry can be found in SN 25.1
One who has conviction & belief that these phenomena are this way is called a faith-follower: one who has entered the orderliness of rightness, entered the plane of people of integrity, transcended the plane of the run-of-the-mill. He is incapable of doing any deed by which he might be reborn in hell, in the animal womb, or in the realm of hungry shades. He is incapable of passing away until he has realized the fruit of stream-entry.
About Cula-Sotapanna, Piya Tan's comment on SN 55.24
The Buddha goes on to list six categories of persons who are assured of liberation, namely:
(1) arhats, (2) non-returners, (3) once-returnres (4) stream-winners, (5) [truth-followers] those who accept the Dharma only after pondering over it with wisdom (dhammā paññāya mattaso nijjhānaṃ khamanti) who do not have quick and sharp wisdom and have not attained complete release, but who do possess the five faculties (pañc'indriyani) of faith, energy, mindfulness, concentration and wisdom [sutta §11]; and (6) [faith-followers] those who only possess the five faculties but who have mere faith (saddhā,matta) in and mere love (pema,matta) for the Buddha.
The elder monks of old (poraṇaka thera) call such spiritually developed persons like (5) and (6) as "lesser stream-winners" (cūḷa,sotāpanna) or "maturing stream-winner" (bala,sotāpanna).
Cula litterally means small, less, tiny, microscopically small. No record of Bhuddawajana (words from Buddha) of cula sotapanna. It is later addition to pali cannon. Personally I am very careful about later additions because it is not from Buddha. One example of the danger of later additions, in 12 sutta, Buddha did not allow monks to make holy water but in 1 sutta, he himself gave his alm bowl to Anandha to make holy water. that odd sutta is a later addition. I dont know if i opened up a can of worms with my personal thoughts.
Back to the question, Faith follower is one who firmly believes in Buddha's teaching that all things perceived by each faculty is not permanent and subject to decay and ending, and shall never die before reaching sodapanna. Buddha categorized sotapanna into how many times he/she would return before reaching the enlightenment. He did not use word "cula". here is a free book about stream enterer. the author compiled the sutta which are reasonably believed to be Buddhawajana.