Don't misspell your grandmother's name. You are absolutely spot-on with the question, "Who wants to have a name they have to spell out to everyone?" The answer is no one. The original spelling of the name looks much nicer; I wouldn't modify it to have 8 letters or repeating letters. Use it as is or ditch it.
I honestly think this pattern is so subtle that you shouldn't feel obligated to follow it. I would have never noticed if you hadn't pointed it out.
As far as suggestions that meet your criteria...DD2 is Tallulah.
There's also:
Vivienne
Marianne
Collette
Ellison
Arabella
Juliette
...I got nothing. This is a hard pattern to follow. If you didn't mean to do it with the first three, I wouldn't make a point to do it with #3. Just my two cents.
Don't change Alicia!
If you like Alicia, spell it as Alicia.
Honestly, I wouldn't have known the pattern existed until you pointed it out. If you want to keep the pattern, the pps above have given great suggestions, like Juliette, Allison. There's also Julianna.
ETA: Sorry...Allison is just 7 letters. I forgot all the rules.
Don't use a misspelled version of your gmas name.
Either break the "pattern" or use different names
Carmella Leigh
Callista Gale
Daniella Hope
Susannah Eve
BFP 1- EDD 2/09/11 Missed MC DX @11 weeks D&C- 7/25/10 BFP 2- EDD 12/22/11 Natural MC @ 5w 2d BFP 3- EDD 1/25/12 DD Josephine born 1/16/12

Re: 8 letter baby girl names with a one syllable middle name.
No, do not change the name of an existing name like Alicia to make it into an 8 letter name. That's ridiculous. Aleeysia is a TERRIBLE NAME.
There are plenty of real 8 letter names if you'd like to continue that pattern: Jennifer, Caroline, Kristina, and Coraline come to mind. There are others. Either use a real name with a legitimate spelling, or forget the 8 letter thing.
Eve is fine for a middle name for almost any first name.
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Gulianna
I like Eve but also what about Faye?
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