@Trailblazer Jesus (a) said he was the light of the world so long as he was in this world. After he left earth (whether dead or risen), who was the light of God on earth? Who was the path?
I believe the subtle bringing of Elijah (a) with Moses (a) and talk about John (a) being killed from before, is to say, Elijah (a) is here, but won't be recognized if goes public and will be rejected same way Jesus (a) is rejected, and that disciples who witnessed Elijah (a) is that since Jesus (a) is ascending someone has to be on earth as the path and light. The talk of Yahya (a) (John) was to say Elijah (a) won't be accepted but he is here still.
This is the wisdom of the two places Elyas (a) appears in the Quran.
وَزَكَرِيَّا وَيَحْيَىٰ وَعِيسَىٰ وَإِلْيَاسَ ۖ كُلٌّ مِنَ الصَّالِحِينَ | and Zechariah, John, Jesus and Ilyas—each of them among the righteous— | Al-An'aam : 85
Yahya (a) succeeds Zakariya (a), Isa (a) succeeds Yahya (a), but why mentioned Elyas (a)? This is because Elyas (a) came back and when Isa (a) ascended, it was Elyas (a) who became the guide, witness, and light although hidden from public.
The other place Elyas (a) is mentioned in Surah Saffat in which Isa (a) oddly is not mentioned. There is subtle wisdom in all this.
As for the outward religious leadership, Simon (a) was the one to take that role. But Simon (a) is a disciple, not a proof of God sent by God nor chosen before coming to this world. He was selected by God and Jesus (a) in this world, which is different then the pre-chosen type.
After him Paul (a) took place of leadership, but eventually, the leaders of the church ended up teaching trinity. I don't believe Paul (a) was such from reading his words, but who knows.
I think there is a misunderstanding between Bahai and Shiite belief of the path. Per hadiths and Quran I believe the path is always by a living instance of it. While your Prophet made it more about Nubuwa, the hadiths (and I believe Quran does same) made it more about connecting to the leader of the time and recognizing his spiritual link to all humans and Jinn.
So today, it's Imam Mahdi (a). The Du'as teaching us to pray to be guided by his hands is not only du'as attributed to him, but for example, Imam Reda's (a) du'a:
Du`a Allahumma idfa`an waliyyik in occultation -by Imam Reza(as) Duas.org
Bahais see it more like teachings of a (dead) guide is the guidance, while my experience, is teachings become quickly locked in time and irrelevant. You need current guidance in real time. Hadiths are a coping means and a means of Imam Mahdi (a) working through people to guide others, but they are not sufficient. Even Quran which is absolutely protected cannot guide in these times alone.