Photo editing

I need to put together 4 photos for the carousel on the homepage of my website. It is the awkward 900 x 450pxl so I want to make 3 photos:

1. Extend the background of two photos to the side to make it the right size and add text over;
2. put 3 photos together to make one. The furniture will need to be cut out of each of the current photo set ups and put onto a coloured background. Will need two of these.

So basically, just a bit of cutting out, placing and resizing.

Couple images attached for reference