Global talent visa for dependents validity

Hi guys,
I am on the verge of applying for my global talent stage 2. Now due to financial constraint, I plan to apply for 3 years as the main applicant and maybe 1 or 2 years for my wife and son (so as to cut down on the IHS fee).
Here are my questions:

  1. Can I apply for less duration, 2 yrs, for my dependents and pay the IHS fee as such?

  2. How do I do that online without providing lying about my own duration, so as to get IHS fee for 2 years.

  3. How can this be done, since we don’t have money to pay for 3 years for everyone., and I really want to apply for 3 years( not negotiable).

Thanks and best regards

Albeit late, @Damian what did you end up doing? Were you able to apply for less/more duration for your dependants?