VuLLs stop going off topic, you have a whole other thread for your Vegeta ideas.
Krillin never ascended, the trans' they added in the game was made up so that Krillin would be a balanced character, so of course he can descend, you say it would be stupid for his hair to dissapear, don't you think it's strange that it just appears in the first place?
Anyway, you didn't clear up the Piccolo thing;
Pre-Dragonball:
-A Namek came to earth, you do not know his name
-He went to the lookout to talk to the Kami
-The Kami said that there was too much evil in the Nameks heart
-The Namek creates the blackstar dragonballs
-The Namek doesn't split in two, but removes all the evil from his body in the form of another Namek, this is Evil Lord Piccolo.
-The Namek wins against Garlic for the title of Kami, he takes the name Kami.
-He seals the blackstar dragonballs in the lookout.
-He creates the new dragonballs (red stars)
Dragonball
-Evil Lord Piccolo is killed by Goku. Before he dies he pours his essence into an egg.
-The egg hatches, this new Namek is called Piccolo.
DBZ:
-Piccolo fuses with Nail, keeps the name Piccolo.
-Piccolo fuses with Kami, making them the original Namek from the start, however he does not remember his name, so keeps the name Piccolo.
Long story short: Piccolo can divide and fuse as he want's so he should be able to descend
