@azurial, one possible solution to the link issue is to grab the link from the browser bar rather than the pop up window. First make sure you’ve set it to public in the pop up window, then close that window. Then make sure you have clicked on the page with the activity on it, and then copy the link from the normal place (see image below):
Re the issue with the column. You can’t use the Reuse/Upload option within the column activity. However, you can copy the whole dictation and paste into the column. First, go to your Dictation activity and click on edit. At the top should be an option to copy like in the picture below. click that:
Once you have done that, go back to your list of activities and open up the Columns one and click edit. Then at the bottom click Add Content, you should then see a Paste option (see picture below). Click that and it should paste the dictation activity into the Column. Bit of a faff I admit, but it does work! Let me know how you get on.