I think it's important to establish the importance of the elements you want to use these backgrounds for. Like Ryan and TehYoyo have pointed out; Using multiple backgrounds via CSS will only work in modern browsers, meaning it'll not work in legacy versions of IE (IE8 and under) and old versions of Firefox, Opera, and Safari.
So, if you're using these backgrounds for mere decoration, as you noted, then it shouldn't matter much.
You should definitely use a background color to go with your background images, should text be involved. The best way to find out whether your site is usable with the absence of these backgrounds, is to turn off images. If your site is as usable as it was with these backgrounds, then you should be safe.