Yes. In Palworld v1.0.3, Lyleen can get Ferocious through currently verified methods: it is in the standard random pool. Ferocious is in the standard random passive pool in v1.0.3, so it can appear on a caught or bred Lyleen and be inherited from parents that have it. The facts behind this answer are graded B and come from 2 registered sources.
Reason
Attack +20%
Rank
3
Random pool
Yes
Other Pals
299
Lyleen breeding recipes
1
Fixed passives on Lyleen
1
Custom slots available
3
Verified evidence claims behind this verdict
2
Lyleen parent pairs with a direct source of Ferocious
1 of 1
Ferocious breeding route for Lyleen: 1 of 1 parent pair include a direct source (Lyleen).
Why
Ferocious is in the standard random passive pool in v1.0.3, so it can appear on a caught or bred Lyleen and be inherited from parents that have it.
How Ferocious can be acquired on Lyleen in v1.0.3
Current method
Available for Lyleen?
Note
Fixed / innate
No
Lyleen is born carrying Spirit Emperor, not Ferocious.
Random pool (catch or hatch)
Yes
Ferocious is in the standard random pool, so it can appear on a caught or hatched Lyleen.
Implant (Surgery Table)
No
Ferocious: no verified item method grants it here.
Breeding inheritance
Yes
Lyleen can inherit Ferocious along a verified breeding chain, under the standard passive-inheritance rule this dataset has not independently sourced.
Verdict per requested component on Lyleen in Palworld v1.0.3
Ferocious is in the standard random passive pool in v1.0.3, so it can appear on a caught or bred Lyleen and be inherited from parents that have it.
B B · 1 source
How it reaches this Pal
Ferocious is in the standard random pool, so it can appear on a caught or hatched Lyleen.
299 Pals obtain Ferocious directly in v1.0.3 (Demon Eye, Depresso, Digtoise, Dinossom and Dinossom Lux).
Lyleen breeds only from two Lyleen parents in v1.0.3, so no other species can bring Ferocious into its line.
5 of 299 shown
What you can do now
Ferocious is in the standard random pool, so it can appear on a caught or hatched Lyleen.
Alternative: Lyleen can inherit Ferocious along a verified breeding chain, under the standard passive-inheritance rule this dataset has not independently sourced.