Is the wife considered a wife Islamically after her husband told her, "I have taken you back," during her 'iddah, taking into account the issuance of a divorce decree from the Finnish civil court after he had told her, "You are divorced," and he did not reconcile with her before the divorce was documented?

As long as you returned your wife before the expiration of her iddah (definition) (waiting period) from your revocable divorce, she has, in Islamic law, returned to your marital bond, and one divorce counts against you. The divorce certificate issued by the court is of no consequence. The iddah begins from the time of the divorce, not from the time of its documentation. It is advisable to document the reconciliation in court to safeguard the wife's rights.