Welcome to the forum.
Adobe Premiere Elements is a video-editing program.
From the list of operations that you gave, it appears that you need another Adobe program, Photoshop Elements, an Image-editing program.
Do you also have Adobe Photoshop Elements, along with Adobe Premiere Elements? The reason that I ask is that Adobe offers a bundle with both of those Elements programs included - but they also sell the two Elements programs separately too.
Good luck, and let us know if you also have Adobe Photoshop Elements, in addition to Adobe Premiere Elements.
I do not use the PDF format to any great extent, but here are my immediate observations on what you posted...
Photoshop Elements should meet your needs for opening a PDF with photos and text, and even editing the photos in the opened PDF. But I have not found it possible to edit the text that came along with the photos in the PDF that has been opened in Photoshop Elements. (I am using Photoshop Elements 11 as my model.)
However, I have found that I can add text to the PDF opened in Photoshop Elements. And, after I save the PDF with edited photo and added text as PDF, I can reopen that PDF in Photoshop Elements and edit the text added in Photoshop Elements as well as edit the photo further.
Premiere Elements is definitely not the program that will meet your current project description. As for a program that would best serve your overall needs....
You might consider posting in the Photoshop Elements Forum at Adobe to get some insights there.