Is it permissible to reconcile with the wife by word and by intercourse during her waiting period ('iddah), and what is the ruling on intercourse during it, if the divorce was finalized by mutual release (ibra')?

Divorce in exchange for exoneration (طلاق على الإبراء) is a compensatory divorce, where the wife waives her financial rights in exchange for the divorce. This divorce is considered irrevocable (بائن), meaning the husband cannot take her back except with a new contract and a new dowry. What you mentioned about receiving the deferred dowry (مؤخر الصداق) and furniture does not align with your statement that the divorce occurred through exoneration. It is advisable to present the matter to trustworthy scholars in your country.