Can electrostatic interaction affect nucleophilic attack by thiolate anion
It would since the S atom is now negatively charged. However, S is a very poor hydrogen-bond acceptor as evidenced by its weak basicity (thiols are more acidic than alcohols). So this electrostatic effect will be greatly diminished if you compare with more basic nucleophiles like F- and O-. This is because sulfur larger and will be more polorizable making the localization of the negative charge more disperse around the atom and much weaker to form ion-ion interactions. It will still remain as a relatively powerful nucleophile, so you can expect side reactions.