Interesting list!
I am, however, about to rubbish your list and give you a bigger headache! This isn't to be nasty but to get you thinking and try and get some of those associations out there for you. Don't take it too personally! I think if you still love one of these, go for them regardless but be aware of the pitfalls.
Aggie, Agatha - I like Agatha but not Aggie. I think Maggie. Which is Maggie Thatcher.
Ana, Anastasia - I like Anastasia. I also am fond of Arianna / Ariana.
Cecilia - Try saying it with a lisp... Its difficult to say full stop without sounding like you have a speech impediment. Cicely is a nicer variant too.
Clara, Claribel - Definitely Clara of the two. Claribel is someone who couldn't decide between Claire and Isabel and ends up with a cow.
Clementine - ...Oh my darling, oh my darling, oh my darling Clemennnntttinnnne. Prefer Celeste
Cora, Flora - Of the two I prefer Cora. Flora is another cow or a brand of margarine. I also prefer Coraline which I have a feeling will be up your street or Coralie or Cordelia.
Emmeline - Trying to make Emma/Emily sound posh. Would suffer from having to clarify which variant she was.
Eva, Evangeline - No. Just it and its varients are all WAYYYY to popular. Its worse than Emmeline for it. She would forever be telling people which one she was.
Georgiana - Same problem as Claribel. Either go for Georgia or Ana (or similar)
Ida - Eiderdown. Prefer Ada or even Adeline since you seem to prefer long names that can be shortened.
Lucretia - Not for me. Another poshing up of a perfectly good name, Lucy and its not a particularly pretty sounding one either. Go with Lucia if you want something along the same lines.
Millicent - Quite nice actually. Can't think of anything problematic.
Minerva - a brand of contraception.
Octavia - Skoda
Ophelia - I feel your balls. Nuff said.
Persephone - No. Percyphone is god awful and people will call her Percyphone.
Rosa, Rosalie, Rosetta - Pretty enough. Rose, seems to be the middle name of choice though so could feel a bit bland with her peers even if you go with Rosa. I do think gypsy a bit too. Prefer Rosalind to Rosetta.
Viola - Can't get away from it being a small Violin. And it just wants to be Violet which is going to be enormous. And it reminds me of Violent.
So my 'short' list version of your girls names would be:
Anastasia, Ariana, Cicely, Clara, Celeste, Coraline, Adeline, Millicent & Rosalind.
Albert, Phillip - Both too Royal for me. Albert makes me think of a Prince Albert piercing. Phillip is under used at the moment in my book but I don't think Prince Phillip, the Royal Foot in Mouth association is a good thing. I would image there will be a rash of them when he does cark it, which considering his age won't be too far off.
Clarence - Nothing wrong with it in my book, though not to my taste. Would be Clarry which I don't like. I prefer Clement or Laurence (Clemy or Laurie/Larry). -
Francis - Again, love. Its a family name and we nearly used and if we ever did have another boy (we won't) they would have this as a middle name. As a first name they would be Frank (because Franny is horrendous) though, so you'd have to be happy with that. Beware the current Pope is Francis, though I don't think this is a problem for me, because as far as Popes go, this one isn't doing too bad.
Ernest, Edgar, Everett - Echoing the Nooooo for Edgar. Edgar Allan Poe. Dark and Foreboding. On the other hand I LOVE Everett and Ernest. I shyed away from Ernest, as I wondered if it reminded me of the word earnest too much and would be a bit too serious for a child to carry off.. Everett is my favourite of the three and due a revival in my book. Means brave like a boar. I may be a little bit in love with it.
Horace, Hector, Humphrey - Horace erm, no. Humphrey, I think of Camels and humps rather than big grey wrinkly animals, but still the same train of thought. Hector is the best of the three and I'm not terribly fond of that. Plus Horace reminds me of an obscure video game for the spectrum called Hungry Horace...
Wesley - Yuk. Wesley Snipes. And it reminds me of that other horror that is Wayne.
Cecil, Roland, Percival - Cecil forever a lion now. Roland Rat. Ronnie is better. Percy Pig. Nuff said.
Wilbur, Wilfred - Not keen. Slightly prefer Wilburforce, but not keen on that either. Wilf is cute. Wilf is a wolf. But he might end up as Will, which would be a bit sad.
Cornelius - Hey Corny! Nope.
Casper - The friendly ghost. ^Jasper* is better.
Aldous - I think its one best left in the past tbh. People are too unfamiliar with it. Though, for me, Fred Aldous, is an amazing craft shop in the Northern Quarter of Manchester..... .
Bennet - Trying too hard not to be Benedict which is better. Think would end up being shortened to Benny rather than Ben.
Silas - TV Baddie. Murders people. Sylvester if you can get past Stallone (hey he usually plays the hero at least!), or Seth.
My 'short' list for boys would be:
Clement, Laurence, Ernest, Francis, Everett, Wilfred & Jasper
All of which is probably about as useful as a chocolate teapot as its about YOUR taste and not mine.