Moving from Drupal to WP – a good idea?

Dear community,
I am an amateur-website developer and have been using Drupal for all my projects so far… I love it for its flexibility (although there is always a lot of custom php-, css- and html-work), but a new client offered me a project (and maybe a few ones more) that should be based on WP. So, I am now thinking of moving from Drupal to WP completely, as there are so many beautiful and good-working WP-sites around… i know, that this WP/Drupal/Joomla/Typo3-stuff has been discussed a billion times before, but I could not find a satisfying, concrete answer to my problem:

As I said, I dont have any “deeper” experience with WP and my client wants to build me a “onepage”-website that comes with a slider (images and a movie) in the header and below, two sections with respectively one background-image (exchangeable by non-technical editors) and two links to pdfs, that also should be exchangeable by non-tech editors. Sounds easy… but, (in WP), I have absolutely no idea how to start with this project…. I started to look around for themes and found some good-looking ones (such as the “two-fold” theme) that are close to what is in my mind… but – and this is the main question – is WP a good choice (in general) for building sites with a CUSTOMIZED back- and frontend??? Regarding the planned website above: I installed a good-looking theme (with all these beautiful parallax-, fading-in and fading-out effects that I would love to implement) but was struggling with customization beyond the “font-size/font-color/background-image”-level… WP seems to offer nice “quick-and-easy” solutions to adapt all that “surficial” stuff (text, colors, images), but is it also a good soultion to build customized websites that contain, for example, individual sections not standardly implemented in a “out-of-the-box”-theme? Getting concrete: lets say (using a popular theme like “hestia”), I want to implement an additional, custom block/section underneath the header that shows the result of a DB-query (such as the file-names that are linked to the raw-pdfs, that have been uploaded by non-tech users in a customized back-end)… do I have to make a “hestia”-child and implement all that stuff (customization of the front- and backend) on the SQL- and PHP-level manually?

Don’t get me wrong, please – I am not asking for an “easy step-by-step” solution helping me with my concrete problem (… I am familiar with PHP, SQL, CSS and HTML and def. willing to “dig deeper” into WP!!!); I would just like to know, if those WP-experts out there would recommend WP (maybe over Drupal?????) as a CMS that allows building sites with a customized front- and backend (including all that stuff that I mentioned before: for example: showing the results of DB-queries in a custom section of a theme, building a customized backend that allows non-tech users to upload/edit content or customizing themes and so on).

… if you recommend WP, maybe you could recommend some tutorials or literature to start with??? Thx!!

Thx for any help with this, greetings, flashpanhunter!