Is it permissible for a grandmother to gift her granddaughter land or her share of her properties, in the presence of other children and with the mother's consent?

The preponderant view, in our opinion, is that equality in giving (hiba) is obligatory only among one's own children (children of the loins). As for other relatives, equality is not obligatory among them.

Therefore, there is no objection to your grandmother bestowing upon you some of her property during her lifetime, to the exclusion of her other relatives, unless she bestows upon you with the intention of depriving some heirs, in which case it is not permissible for her to do so.