I think that you need to add an instance variable to your enemy. In this case it will be a number with initial number 45. After you insert a text object and you put it invisible. You go to your event sheet and you do when player kill enemy, set text visible
set text (you go in your objects above, you click on the enemy and you choose your instance variable,45)
Wait 5 seconds (for example)
Set text invisible
I will try to see for the bar,because about that I don't now much
Sorry if it doesn't work I am a beginner