Go for Mee Toh. My first point, echoing the other response, co-ed would be easier if you have children of different gender.
Not sure about now, but 10 years ago, Mee Toh prepared my cousins for NUS High and 100% of their cohort given option to sign up for Math Olympiad held in the school every year from P1. Both went on to Nanyang Girls and they do like their time at Mee Toh. Mee Toh has also got long running E2K programs from my cousins’ time there.

My kids are in Nan Chiau Pri and NCPS only participates in Math competitions for P4 onwards. From my P1’s batch this year, NCPS is also no longer doing HCL from P1. My older kids did. My eldest is also in NCPS E2K program. With the scrapping of GEP, our principal informs that going forward, for entry into E2K program, first priority will go to students in the name list handed to the school by the MOE Gifted dept, then review of results+recommendation from the teachers.

So if you are looking for a school to support high flyers, I’ll just say that the high flyer graduates from Mee Toh recommends this school. They also have the E2K programs that seem to be replacement for GEP. Maybe grass is greener on the other side, from what I have heard, I even feel like Mee Toh might be better than NCPS.

I assume Nativity refers to CHIJ OLN. If you don’t have any son(s), it’s a good option as it’s affiliated to CHIJ SJC, which is also in the SK area. If you do have male children, you should consider MTS or Rivervale, whichever is most convenient to you.