Rule 19 of Non-Contentious Probate Rules (Cap. 10A) states that :   The person or persons entitled to a grant of probate or administration with the will annexed shall be determined in accordance with the following order of priority, namely-   (i) the executor;   (ii) any residuary legatee or devisee holding in trust for any other person;   (iii) any residuary legatee or devisee for life;   (iv) (a) the ultimate residuary legatee or...