Good day,
I have 12 years of experience working with PHP, 9 years on Joomla, implementing templates, modules and components for versions 1.0.x through 3.
The way I normally work to create new modules and features, is I first specify your needs on a simple, yet detailed document which we can both agree on (use case / uml if needed), before writing a single line of code. This has helped me a lot in the past to provide consistent succesful deliveries to my customers, but I am flexible, and if you prefer another methodology, I'd be happy to comply.
Looking at the document with all tasks taken into account, I'd estimate around 4 hours of work, assuming the component that needs to be modified is something I haven't worked with and that I'd have to get to know it intimately, before doing the actual work. Tasks 1 and 3 are probably the trickiest, task 2 should be breeze. But rest assured I've done similar things in the past with several other components like Community Builder, VirtueMart, JoomGallery, to name a few.
Also, I'm proficient in both english and spanish, with hardly an accent, so if you speak either of those languages fluently, communication should be a breeze! I've found this to be extremely important when working with teams abroad, and I'd respectfully suggest you take this into consideration when hiring.
Thank you for your time and consideration for your project. I hope to be doing business with you soon!