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
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