Is there any way to use different fonts in a title, or to make parts bold, italic, different color?

I use Inkscape for graphics and titles for kdenlive. It works well and is more flexible. go to "file" "template" for the 1920x1080 screen size. Each line of text will need it own "block" or weird stuff happens.

True, use Inkscape for more text flexibility. Be aware of the cairoblend alpha bug that may bite you when using Kdenlive's new transparent tracks with unpatched frei0r plugin packages. Your frei0r needs to have the mid-November 2015 alpha patch. To work around, simply use an explicit alpha or composite transition to overlay a title or SVG clip with your video clip.