ESF schools aren't much help for the 1st year as your child will be in kindy, as you said.
There are 3 kindys that your child could attend in DB, none are ESF including DBIS, which has a kindy/pre-school. The standard debenture is $30k HK if there is a spot for your child. After 3 years you get zero dollars back for it. (NOT much of a debenture...)
Another option at DBIS is to pay a capital levy each year of $10k, again if a spot is available. (Doesn't make much sense if you planning to have your child attend for more than 3 years).
The other option is the premium debenture, for $150k. You are guaranteed a spot with this one and it is on-saleable. The only problem would be finding someone to sell it to. There doesn't seem to be a limited supply and if the new school opens and relieves the pressure on enrolments in DB...
It is true that they are planning to open a new school in DB from years 1 - 13 and that it is ESF. The only problem is that there are no start dates for construction and nothing has been finalised. It is to be called an ESF International school which means that there could be debentures and the fees will be higher than a normal ESF school.
Clear as mud?