Are you getting on another international flight the next day?
If so, then if I were me I'd bite the bullet and spend some extra $ to stay at Royal Park Hotel. Royal Park is right at the international terminal, which will make it very convenient for you both upon arrival and departure. Plus it looks like you'd be having meals at the international terminal landside shop/dining complex. Finally, having done countless TPAC flights with little kids, I can tell you that there's a chance your little ones will wake up in the middle of the night. If that happens, as freecia suggests, it may be nice to be able to walk to a 24hr konbini. There's at least one landside inside the international terminal.