Customisation of website forms (html)

General information for the website: Travel Agency
Description of requirements/features: Hi!

I will be buying this: http://themeforest.net/item/annova-survey-wizard/6329118
I own an online travel agency and when a customer wants to travel to one of our destinations they must fill in a form with their details and the details of other individuals they are travelling with!

Your job is to create these forms with the same questions as our current forms (currently at 123contact forms) I can provide links :)

There will be 5 versions made for 5 different holiday destinations. 4 of them are pretty much identical! The 5th one is a custom questionnaire with a few extra questions.

Must be able to use on mobile, tablet and desktop
Same font and style
Must be compatible with our current website (wordpress) can show you upon request

Complex part:
When a person selects 4 travellers > 4 sections of questions must be made available.
If a person selects 8 travellers> 8 sections of information must be made available. etc etc

In your response please outline how you will do this task. Thank you :)
Extra notes: