What 少数で島いっぱい means?


I am not sure about the meaning of modifier 少数で島いっぱい here

>
> 桃太郎は宇宙人で、母星の爆発から、桃によく似た形の宇宙船で脱出し、地球へ辿り着き、人間に擬態して生活していたところ、鬼退治を依頼された。それなら他の生命体の言語を理解でき、
> **少数で島いっぱい** 鬼を倒せたのも説明がつく。

Does 少数で島いっぱい鬼 mean few oni that is as big as an island? Not sure what いっぱい is
doing.




It should be 少数で島いっぱい **の** 鬼.

Structurewise, 島いっぱいの鬼 is the same as 部屋いっぱいの花 = room-full of flowers (flowers
filling up the whole room). So it means _oni's abundant in the whole island
(island-full of demons)_

少数で refers to the fewness on the 桃太郎's side. They were a dog, a monkey, and a
[green pheasant](https://ja.wikipedia.org/wiki/%E3%82%AD%E3%82%B8) and
himself, so just four of them.

So the last part says _(If Momotaro was an alien), it is explainable that they
understood the language of other beings and was able to beat **the whole tribe
of oni's with so few** (on their side)_.




It should be 少数で島いっぱい **の** 鬼.

Structurewise, 島いっぱいの鬼 is the same as 部屋いっぱいの花 = room-full of flowers (flowers
filling up the whole room). So it means _oni's abundant in the whole island
(island-full of demons)_

少数で refers to the fewness on the 桃太郎's side. They were a dog, a monkey, and a
[green pheasant](https://ja.wikipedia.org/wiki/%E3%82%AD%E3%82%B8) and
himself, so just four of them.

So the last part says _(If Momotaro was an alien), it is explainable that they
understood the language of other beings and was able to beat **the whole tribe
of oni's with so few** (on their side)_.

