At first glance, when I saw the Japanese name アルベル, my first thought was that it should be Alber, even though TCB translated it as Arber. Then I saw in Wiki that it could be Arbel, and frankly, it blew my mind.
First, let's look at the pronunciation:
When names in English end with -er, like "Chopper" for example, they are usually written with the letter ー, which is elongating the last vowel (Choppaa).
When names end in el, like "Enel", they are usually written with the letter ル (Eneru).
This rule is not set in stone, but it supports the Arbel option.
Second, there's a One Piece filler episode with a female character named Arbell. Her name is Japanese in Wiki is アルベル, exactly like our King's.
Now, let's look at the meanings of all the name options. I know what Arbel means, so I googled the other names and here's what I found:
Arber:
The name Arber is rooted in the ancient Anglo-Saxon culture. It is a name for someone who worked as a person who ran a lodging house. This surname is a metonymic form of the surname Harberer, and is derived from the Old English word herebeorg, which means shelter or lodging.
Doesn't sound to me like anything to do with King.
Alber:
I didn't find such a name without the ending T, it seems to me like a French or other pronunciation of the name Albert.
Albert is a masculine given name. It is derived from the Germanic Adalbert and Adelbert, containing the words adal ("noble") and beraht ("bright", compare Robert).
Do you think "noble" and "bright" describe King? Umm... could be but these are not the first words I'd use to describe him...
Arbel:
https://en.wikipedia.org/wiki/Mount_Arbel
Mount Arbel (Hebrew: הר ארבל, Har Arbel) is a mountain in The Lower Galilee near Tiberias in Israel, with high cliffs...
As you can see in the picture, mount Arbel looks very similar to the Red Line, where King's tribe is said to have originated from. Also, the Holy Land resides on the Red Line cliffs, while Mount Arbel resides in the real "Holy Land" - Israel. I think it's cool if he bears the name of the place of his origin. Besides, as an Isreali myself, I'm biased. I adore that name.
So my choice is definately
Arbel.