Yes, Herzl himself referred to Zionism as a colonial movement. In a 1902 letter to Cecil Rhodes:
You are being invited to help make history. It doesn’t involve Africa, but a piece of Asia Minor; not Englishmen but Jews … How, then, do I happen to turn to you since this is an out-of-the-way matter for you? How indeed? Because it is something colonial.
The first Zionist banks were called “Jewish Colonial Trust” too. The nascent Zionist movement was always an openly colonial project. I suppose now that colonialism is not the cool thing to do anymore some Zionists are shying away from the term, but some still do openly identify their politics that way.
No, there is simply no such thing as “zeroth”, that’s not how ordinal numbers work. If I have the following numbered list:
Foo
Bar
Baz
The first item is “Foo” which is indexed 5. It is not the fifth item, because the item indexed 5 comes first in the list, so the item indexed 5 is the first item. Ordinal numbers don’t refer to index, they refer to order.