Is it safe to delete files imported from iPhoto? I did not set up a file naming convention beforehand. Alternatively, is it possible to apply file naming conventions after import?

Adobe seems to be asking me to ask my question again, so here goes , repetition rules OK - I enthusiastically imported my photos from iPhoto into Lightroom.  I thought I'd imported them all, but the numbers don't match up...  I omitted to set up file naming presets/conventions.  Can I do this after import?  Can I delete the imported files and start again?  Lastly, does anyone know why Lightroom jams when I try to reset my location from the USA to the United Kingdom?  I am NOT in the USA but in London - and it might be more appropriate to speak to local support staff than staff in a very different timezone.  I may go grey/bonkers before this is resolved!