Show me your evidence the plural pronouns in Genesis are fictitious? Surely you have some reason for your claim, right?
Oh dear! Oh dear! I'm guessing English is your first language is it? If you have so much trouble parsing a simple sentence in English, how can you possibly hope to understand the language of the Hebrew Bible?
Anyway, I did not say that the plural pronouns were fictitious, I said the quotes were...do you really want me to get into the evidence against the veracity and reliability of transmission of the text of the Bible on which your quotations are based? I'm not going to anyway - there are plenty of resources for you to research that for yourself - and its fine if you choose to believe it to be the verbatim Word of God but...
The use of plurality seems to be used fairly routinely in the Bible to express - possibly - either:
Excellence -
pluralis excellentiae - the use of
Elohim (or
Adonim) in the plural with a singular verb or adjective - God - not gods - said or did this or that...which is, as I suggested analogous (though not exactly the same) as the "royal we" (
pluralis majestatis) which is common in a number of languages (ancient and modern).
or, deliberation - such as in the two cases you cited - "God (Elohim -plural) said let us (plural)..." - IOW God - in his excellent majesty (denoted by the plural Elohim) is deliberating with himself...there is no support for plurality of persons in this - its just a literary device.
If you insist on reading pluraility of persons into these, you have a problem with verses such as Isaiah 19:4 where Yahweh (singular) declares that he will deliver Egypt into the hands of a cruel (singular adjective) master (
adonim plural noun), and a fierce (singular adjective) King (singular noun)...
adonim (being the plural form) would then (to be consistent with your understanding of Genesis 1:26) have to imply that this "fierce King" would be more than one person...
Anyway, like I said, one has to exercise caution in using literary devices to prove (or disprove) theological claims - I think the plurality of nouns and pronouns in scripture is almost certainly entirely irrelevant to the plurality or oneness of God.