Question: How many names did Nabi (S.A.W.) have? Furthermore, can the attributes ‘Al-‘Awwal and ‘Al-Aākhir be used for Nabi (S.A.W.)?
Answer: From the books of Ḥadīth and Tafsīr we deduce that Nabi (S.A.W) has over 99 attributes, but just to confirm with the famous names of Allah-Taʿālā, 99 attributes of Nabi (S.A.W.) were chosen.
The meaning of (‘Al-‘Awwal) and ‘Al-‘Aākhir) will differ for Nabi (S.A.W.). ‘Al-‘Awwal will mean either his Rūḥ (soul) was created before all the souls or his Prophethood was announced first.
The meaning of ‘Al-Aākhir will mean that he was the last prophet to be sent into this world.
Lastly, it is preferred not to mention these two attributes of Nabi (S.A.W.), ‘Al-‘Awwal and ‘Al-Aākhir together, side by side. The reason for this is to remove doubts which could occur, because generally, when a person listens to these two words (‘Al-‘Awwal and ‘Al-‘Aākhir), his mind immediately turns towards the normal meaning, which is its use for Allah Taʿālā.
For further details, please refer to:
Fatawaa Darul Uloom Zakariyya (vol. 1, Pg 55-57; Pg 296-299)