What is the grammatical analysis (إعراب) of "ليكونا" in the Almighty's saying: "ليسجنن وليكونا من الصاغرين," and how is it to be recited upon stopping?

The word (liyakūnā) in Surat Yusuf is written in the Mushaf with an alif, and it is a lightened nūn at-tawkīd (nūn of emphasis). The وقف (وقف) or pause on it is with an alif because it is lightened and resembles the nūn al-i‘rāb (grammatical nūn). Similar to it is the word (linasfa‘an) in Surat Al-Alaq, which is also written with an alif. The وقف on these words is with an alif, in accordance with their writing in the Mushaf.