Singapore Expats

My Child(<1yrs) was born in Msia with Msia passport, we tag along his Sgrean application and was approved. Would like to clarify a few item below:
i)Can he continue stay at Msia during Renunciation for both Sg and Msia?
ii)Can he continue use both Malaysia and Singapore passport?
iii) When he back to SG in future(>2yrs), can he exit Msia using Msia Passport while enter SG using SG Passport?

Appreciate your help.

My daughter holds dual citizenship. She has used both her SG and US passports when traveling with no issue. Many people believe that one cannot hold dual citizenship beyond the age of 21, when they’ll need to choose between the two and either renounce their foreign citizenship or relinquish the SG citizenship. I looked into this a while back, apparently it is not actually illegal to continue holding on to both, but the catch is that one would not be allowed to exercise their citizenship rights in the other country (which makes holding onto citizenship pretty impractical, so I guess either way one would need to make the choice). Yes he can exit Malaysia with his MSIAN passport and enter SG with his SGean passport, that’s what my daughter has done this whole time (SG passport when leaving SG, US passport entering US).