The pipe that sucks fuel from inside maybe broken due to rust. check that.
once i had got repaired tank of 81 corolla, same thing happened while installing back. then i had to make a new pipe so that it reaches till the bottom.
if there are no visible rust or dents, i would suggest dont get touchups. as for lights, find in scrapyards near ur area or if found online.
as per the pictures u posted above, the car body seems perfect as well as the back lights. why u want to change them,