Scribus and Latex dont know about these?? Me i use OpenOffice 4.1 and use some other softwares. I have seen some youtube video tutorials to make some basic book template with OpenOffice. For the *.ai file i suggest the free software https://inkscape.org it is a software that can do image that can be vectoriel, some say could be similar to Adobe Illustrator. A free software about creating photos or images is: http://www.gimp.org wich some peoples say is like Adobe Photoshop. There is also this free image soft: https://krita.org. Well i hope that these links help. I know other free and legal softwares, but not sure giving the links here would be appropriate to the subject here.
A+
A+