General rule for when 一 is yi1 and when it's yi2/yi4
The rule of thumb is the following.
When indexing it is yi1. For example

一楼 (first floor)
一声 (first tone)
第一 (the first)
一次世界大战 (World War I)
一来 (firstly)

When counting （the same rule as 不）

it is yi4 when followed by 1, 2, 3 tone

一呼百应
一毛不拔
一百
一扫而光


it is yi2 when followed by 4 tone

一蹴而就
一气呵成



For others, mostly yi1. For example

统一
均一
敬一丹（name）

As a comparison, 二 can be indexing or counting, but 两 is only counting.
PS: Most of the words in the Wikipedia list are right, but there are clear errors. For example &quot;一yi4夫一yi4妻&quot; appeared in 2 lists. And, it should be &quot;一yi4朝一yi4夕&quot;. Don't fully trust it.