May siblings agree to divide the estate equally instead of by faraid?

Yes, provided that all the heirs involved are adult, of sound mind and consent freely without pressure, after each has learned their actual share under faraid. This practice is known as mutual agreement (muafakat) or takharuj: heirs voluntarily give up part of their rights to other heirs. The rights of heirs who are still children or not of sound mind cannot be given up; their shares must be protected. In Malaysia, this agreement is recorded during the estate hearing at the estate unit, Amanah Raya or the court. Make sure every widow in a polygynous family is also present and agrees; do not let anyone be pressured. See faraid.