First, what are those add-ons? Do they have icons? Some don't.

Second; Type about:customizing<enter> in the address bar. In the new window, look for the icon. When you find it, hold down the left button on it, and move it to where you want it to be. You can move any of the icons you want from here, but some icons are locked in place.

I'm not seeing any extra extensions in the System Details list next to the question apart some defaults that come with Firefox.

Application Update Service Helper 1.0 (aushelper@mozilla.org)
Multi-process staged rollout 1.5 (e10srollout@mozilla.org)
Pocket 1.0.5 (firefox@getpocket.com)
Web Compat 1.0 (webcompat@mozilla.org)

Did you use the computer where you installed these extensions?

Do these extensions have a Options/Preferences button on the about:addons page?

Ok, now that's weird. I went to about:addons again, and both of the extensions were no longer there. So I searched for them again, added again and voila! It worked. And the icon got added to the toolbar... I'm not sure what was the issue before... I did try to remove both of the extensions and then re-add them again, but this didn't fix the problem before. Now it's all working! Mystery...

Thanks for the help!

That was very good work. Well done. Please flag your last post as Solved Problem so others will know.