Vayakhel - Names Essence and Oil

Why does Moshe direct the Jewish people to 'see' that Hashem has 'called by name' Betzalel, the master architect of the Mishkan? What is the concept of a Shem-name, and how does it relate to Shemen-oil? Why does the concept of a name denote an all encompassing aspect, whereas oil denotes application? How can oil 'separate' from the name? Why is it better to go to a house of mourning than to go to a joyous party? Why were Chananya, Misha'el and Azarya saved from fire, while Nadav and Avihu were consumed by fire?