Is it permissible to purchase a house from "Devarian" company and obtain an interest-based loan from "BBVA" bank, knowing that "Devarian" will send the agreement to "BBVA" to complete the loan process?

If BBVA bank is a partner with Divarian bank in the ownership of the house, then it is permissible to buy from it in installments; because it is a sale, not an interest-based loan. It is necessary to verify their joint ownership of the house, and that the bank is authorized to sell. However, if BBVA is not a partner, then it is not permissible to deal with it unless it first buys the house for itself and takes possession of it. The fact that BBVA will lend the buyer with an increase (usury) indicates that it is not a true partner in ownership.