Hello Amanda1, Pat from San Diego, California, USA!
It is so much fun sewing for a granddaughter, and a 4 year old is a really special treat for grandmas.
I do recommend getting one of the placement kits. Perhaps you can find someone who ships to South Africa.
For your first question, I recommend that you print out a copy of your design, your software will tell you how to do that. Then you may choose to trim around the design and place the design on the cushion. That will show how it will lay and you can adjust until you like the position.
Don't forget to do a 'test sew out.' This is really important with something that would be difficult if not impossible to replace if something goes wrong. Check my blog on stabilizers for info and tips on how to determine correct materials needed.
Your second question will depend on the design. What you are mainly concerned with is the starting point being in the center of your project. If you center on e.g., the 5" x 4" by folding your template, you can mark your center point and it will be the same for all. I make a small cut in the folded template and match it to my fabric which I also mark the center point. Since you are working with a corner, I recomment still creating a center point for the over all cushion, then decide how far down you want your design center. e.g., after the over all X, measure 3" down from three points of the horizontal X and make a parallel line to that horizontal line.
In this photo, I have already removed my "Perfect Placement" template.
Don't forget to back up your computer and designs, then get to those Christmas items!
Pat, The Avid Embroiderer
If you are interested in selling your projects, you can determine your costs and profits quickly with my Spreadsheet.
If you want a lot of great information on working easier, faster and more confidently on your computer, check out my Tips and Tricks.
If you want to see my pashminas (that I successfully sell retail) check them out here. I also wholesale them.