That's a pretty big question — you might try contacting the creator of each plugin for advice on how to get this to work. If these are paid extensions getting some sort of guidance from the support team is reasonable. If these are not paid extension, then approaching the developers from a "hey, I know this isn't your problem, but I love your extension, do you have any advice how to get this working?" sometimes helps. Paid or free, being clear, friendly and respectful when requesting support always helps.
If I was debugging this for a client I'd start by, (as the comments mentioned), merging the two media.phtml files. Next, I'd run both extensions by themselves to make sure everything is working. Then I'd check if either rewrite or replaces the block associated with media.phtml (var_dump(get_class($this)); from the template), and I'd make sure that both extensions are actually replacing media.phtml and haven't just used the same name in a different folder location.
You also mentioned showInstagramImages "couldn't fetch the value". You didn't indicate is this threw a PHP error (indicative of a block replacement) or if this just didn't work. If it didn't work investigating the definition of showInstagramImages to determine why it didn't work would be useful.
Good luck, and come back with a new question when you've done a bit of legwork on the issue!
As far as I know it is not possible anymore to pass parameters via URL to the share function.
The best practice in my opinion is to implement open graph tags in your website, then facebook is able to extract the correct information. More on open graph tags can be found in the facebook documentation.
https://developers.facebook.com/docs/sharing/best-practices#tags
The most important og tags for your purpose might be the description and the image.
<meta property="og:description" content="MyFavNews is the best source for your favorite news." />
<meta property="og:image" content="http://graphics.myfavnews.com/images/logo-100x100.jpg" />
The upside of the og tags is that they also work if someone post your URL manually on facebook.
Best Answer
you can use share this tool. This will give you icons and sharing links. For sample I have added code here. You can also generate new using this which is free and open source, [http://www.sharethis.com/]
Copy the span tags and place them where you want your buttons to appear in the code.
Copy the script tags and place them inside and at the end of your "head" tag.