The paper is a continuation of the paper by G. M. Gubreev and A. A. Tarasenko [Sb. Math. 201, No. 11, 1599–1634 (2010; Zbl 1227.47011)] devoted to unconditional bases of the de Branges spaces of entire functions of the form \(\{ k(z,\lambda_k),\lambda_k\in \Lambda \}\). Here \(k(z,\lambda )\) is the reproducing kernel of the de Branges space, \(\Lambda\) is a sequence in \(\mathbb C\). In the above paper, it was assumed that \(\Lambda \cap \mathbb R=\emptyset\). In the article under review, this restriction is removed. Related interpolation problems are also considered.