Website needs Salesforce compatible Web-to-lead form created and poss. thank you page

General information for the website: UK Tax return website that needs to integrate with Salesforce web-to-lead
Kind of development: Customization of existing website
Description of requirements/features: We have an identical contact form on 4 pages of our website. The current form is a 'Contact Form 7' plugin for Wordpress but unfortunately this does not have the functionality we require to in order to integrate it with Saleforces web-to-lead function. We also want to track form submissions as conversion in Google Adwords, Google Analytics, Facebook Pixel and Bing Ads. Due to the limitation of CF 7 this has been rather difficult and I need to be advised whether or not this will be possible with another contact form or if I will ultimately require the creation of a 'thank you' page. As I am unfamiliar with Wordpress I am not sure how a 'thank you' page might impact the overall design of the website which I would ideally like to keep unchanged.

The contact form also requires field validation. I want to users to enter a Name, Surname, Claim Type and (Phone or Email). An error message needs to be returned if these conditions are not met highlighting what detail(s) are missing.
Extra services needed: Customization

A detailed overview of the project is as follows:
Form design – We need the contact form designed to look like our current contact form. This will go at the bottom of the Home, CIS, Property and FAQ pages.

Form function – The form needs to be able to integrate with Salesforces Web-to-lead functionality and re-direct to a “thank you” page. I have already provided the coding generated by Salesforce, this includes some custom fields. We also need to be able to track conversions for Google Adwords, Google analytics, Bing, Facebook etc. but hope to do this by inserting tracking code on the “Thank you”.

Field Validation – We need the field validation in place to make (First name and Surname and Claim type and (Email address or Preferred Contact Number)) mandatory. If all the correct fields are not filled in it needs to return an error to prompt the user to fill in the missing details.

Thank you page – A thank you page needs to be created in the same style as our current website. We intend to use the image at the bottom of our homepage with a simple thank you message and a clickable button to take the user back to the home page.

Deadline: Job to be completed by Tuesday 5th April