Very sorry for the delay in getting back to this! For showing the buttons horizontal, there's a few ways to do it. Either create a separate custom module for each button, or add the following CSS to your template:
.sc_twittershare, .jlinkedShare, .jfbclike, .sc_gplusone { float:left; }The problem with that is that it will affect all buttons. You may need to use a more specific CSS selector for that page to make sure it only affects the specific instances of the buttons you want.
As for the G+1 button in Firefox, I'm not aware of any issues with it not displaying. Can you let me know if it shows on our blog for you in Firefox and, if not, let us know what version of Firefox you're using.
Thanks,
Alex