It’s all possible, but it’s all assumptionsActually, the 700 wives were the political gifts, the 300 concubines were not. This is stated very clearly in 1 Kings 11:3 - the 700 wives are described as "princesses" or "daughters of nobility" - in other words, they were the ones given as gifts by kings and noblemen in order to seal alliances with Solomon. The Hebrew word does not refer only to the daughters of kings, but the daughters of any nobility, even "lesser rulers". Even these were wives, not concubines. And the verse specifically states that the "wives" turned away his heart - but not the concubines. The concubines were different.
I take the concubines to be the girls he took on because he actually liked them personally, or because he wanted them as domestic servants to take care of practical matters around the palace. Remember that when David fled his palace, he left concubines to run it - they were his domestic servants, and presumably served the same role for Solomon. So they were selected based on their personal traits - their attractiveness to Solomon or their qualifications for a particular job. They were probably mostly local Israelite girls who had been spotted by Solomon or his officials, though obviously he may have purchased some as slaves from elsewhere. But probably most were local, which is why they were not the ones who led him astray.
Assumptions that condemn a man without proof.