Hello :)
Just read the project description, i have understand project requirement. The main point is create share button with Sticky feature once users scroll to bottom, right ? And, this feature also will avaiable on Mobile
I have Good experience on Wordpress, i know there are good sharing plugins, of course not simply like that. I will need addition coding and implement it into Sticky, require CSS, HTML and Javascript basic knowledge :)
with over 2 years experience on Wordpress, i could help to build your sharing button. Pay on Satisfied or When share button already worked and tested.
Let me know if you interested, for some consideration, please check at review on my profile and some portfolio. Thank you :)