Please be brutally honest...

Glad to hear you (both) like Astrid! Sadly Hazel, Iris and Astrid have been vetoed by DH , so I am pushing for Antonia.
Love these "punchy" yet elegant names.

Oh and I forgot to add Bartholomew to the suggestions list, might be an alternative to Benedict?

So sorry just re-read op, NOT names ending in a

Rita?

Oh, and I know a Hazel with a sister Heather too. There is a third sister in this family though.

Lilith - like it, but will probably be shortened to Lily (trendy)
Iris - okay. Have never met any Iris's.
Ivy - hate it
Laurel - okay. I don't think it's too similar
Helena - love it, but it ends in an 'A'! Thinking of your 5th criteria Don't think 2 'H's would be a problem if the middle name's start with different letters.
Joy - love it
Ellen - like it, but is easily shortened to Ellie, which is kind of trendy

Benedict - love it. Don't know any Benedicts.
Clement - makes me think of oranges.
Hugo - don't like.
Edwin - okay
Ernest - okay
Alec - like this
Gregory - love it. But DH vetoed this one for us because he thought it was too girly.
Percy - don't like. (DH also thought this was girly)
Ambrose - isn't this a brand of custard?
Seth - okay

Amck - I was going to say that I prefer Gregor to Gregory. There is another (similar) Scottish name that I know I like that I just can't put my finger on.

The only Hazel I know has a sister Heather, but I like Hester too. Norah is nice too but does end in an "a" sound as does Lorna which I think goes well with Hazel.

Some of the boys name are a bit "wet" I think to do go with a strong name like Hazel. Alec is nice (it was on my list) and I prefer Gregor to Gregory.

Girls

Love Juliet. Was on my list for dc2 but he was a boy.

Not keen on the rest. Ivy will always be Ivy Brennan to me but obviously not for your daughter's future friends. Lilith, Frasier's ex-wife.

Boys

Love Hugo, Alec and Seth. Edwin is okay. Not keen on the rest

I love Joy (I adore Hope) and Iris out of your girls names. I do think that Iris is on the up though, so would avoid that if it bothers you.
I also agree that Lilith will get Lily.

Out of your boys names, Hugo is cool. I also like Edwin and Seth. I think Ernest and Percy are dreadful. And Ambrose sounds like a cow.

And love Astrid as well

Am I the only one who hates the name Seth??

Seth was the Egyptian God of Chaos and Destruction dotacha know?

Just saying.

Iris
Helena
Hugo
Ambrose

lovely

And congratulations OP

Ruth and Hazel is a good combo .

Also think Hazel and Astrid is good (and equally, Ruth and Astrid).

We must have similar taste, do me a favour and post more boy name ideas - I'm really short of those!

Good stuff - tis firmly on the list, doesn't clash with Ruth, works with our surname, everyone will have heard it and know how to spell it but unlikely to be a dozen of them in their class at school... Ticks all the boxes!

I think there were 70-something Ruths in 2010 and we've yet to come across another toddler Ruth...

Lilith
Iris: isn't this trendy?
Ivy; not keen on this
Laurel: prefer Lois
Helena: also like just Helen
Joy - love
Ellen - love

Boys:
Benedict: I don't know any but Ben is popular.
Clement - no
Hugo - love
Edwin - could grow on me
Ernest - fastest milkman in the west, so no!
Alec - like(ish)
Gregory - love love love
Percy - dreadful
Ambrose - dreadful
Seth - nice

(Oh, and our DD is a Ruth).

Really like Astrid from Magdalena's list too (would be on our list, but another one that clashes with the surname). Cressida would be our 'dream name' for a DD but really really clashes with surname sadly. Serafina was on the list last time but feels more fancy than surname so jars a bit. Still like it, might add it to the list this time.

Boys' names are so much harder - I like Michael, but DH has a cousin with this name and our surname so would be a bit weird! Also like Rupert or Reuben, but clashes with Ruth (can't have two Roos).

Lilith - ok but not great
Iris: love this
Ivy - not keen
Laurel: like this
Helena: like this too
Joy - gorgeous
Ellen - no, sorry

Boys:
Benedict: nice name, like Ben too
Clement - no way!
Hugo - nope
Edwin - old man's name
Ernest = ditto
Alec - dull
Gregory - nope, too 80s for me
Percy - horrible!
Ambrose - yuk
Seth - love this :)

All girls names good apart from Helena. Boys- only really like Seth.

I think Iris and Benedict are already pretty trendy... I know one Iris and two Benedicts under 2.

Lileth makes me think of Frasier.

I quite like Ivy and Hugo.

From your list, I love Iris and Ivy (and Hazel!) - Alec (but I am biased, I have one :o ), Clement and Ambrose.

Do not like the others as much as these, but do not "hate" any of them. They are all nice names.

Others that are on our list and might fall under your criteria:
Astrid
Zelie
Sibyl
Chloe

Etienne
Quentin
Arthur (popular in the UK?)
Louis
Victor

I am expecting DC2 also and am trying to build a list of potential names - one of them is Hazel! Do you meet many other Hazels? I don't like the shortening 'Haze', how do you shorten your DD's name (if you do at all)?

Really like Seth but I know a couple so it's clearly getting more popular. Like Hugo too, would be on our list but it clashes with our surname.

Agree Lilith would become Lily (of which there are really an awful lot, so doesn't meet your 'not top 100' criterion).

Like Ellen and Laurel. DSis is called Joy (and is not 74!)