Shrinking Potions & who are Fred & George?

[meltowne]

No: HPFGUIDX 106683

I was rereading PoA, and came upon the reference to Neville's 
shrinking potion - which turned his frog into a tadpole, and then 
Snape gave him the antidote.

The Shrinking potion de-ages the user, so I bet there are other ways 
of doing this as well.  We've seen one of them in the department of 
mysteries, where the DE went back & forth from full age to baby, and 
ended up with a baby head.  It seems he also ended up with the 
intellect of the baby.

LV was researching was to become immortal, and maybe the aging 
process was part of that research.  We don't really know what 
happened to the Prewetts, but what if LV discovered a way to de-age 
them permanently, as an offshoot of his research?  What if they were 
babies again, their parents dead, and their sister Molly had to take 
them in and raise them (again!)?  We don't really know much about the 
original F&G, but maybe Molly knows enough about them to be concerned 
that they would involve themselves in similar behavior as they grow 
up the second time.  She knows their original fate, and doesn't want 
to see even worse happen the next time.  That might also explain why 
they are not part of "the whole family" who became prefects.

Why did JKR show us the effect of that potion, when we don't know the 
effect of many others?  There are so many references to time.

I also wonder who Harry is - and Tom Riddle.  JKR said that calling 
Riddle the last remaining Ancestor was not a mistake - will he be 
sent back in time to become Slytherin's father?  Will Harry turn out 
to be a young Godric who will go back in time to found Hogwarts?

Was Tom Riddle (the muggle) really TMR's father, or did his mother 
just use his name?  Who was Marvolo?