I think it might be tough on your kids to take public transport across the border every morning. I wanted to recommend Century Bus (school bus service) but I just realised they only ply JB and Woodlands/Sembawang/Yishun areas. If you have the flexibility to work from home, is driving your kids to school and back an option? Everyone will be trying to get their kids to school by 7.15am or 7.30am and that's when traffic is at its peak. At least if they are in the comfort of your car, they can take a nap or chit chat with you. When I had to get kids to school at that time, I found the commute to be the best time for me to connect with my kids. Just my two-cent worth.
Just want to check with you gals if you have gotten into any trouble over sending your kids over the causeway to school cause when I spoke to an MOE person, he told me it is not allowed, either stay in Sg and send to JB for school or stay in JB and send to Sg for school.