Do you want to use these as middles? Or first names? Or both?
I guess it depends on how the name feels to me. I would def love to find middles, but if I found something that really struck me I would use it as a fn!
Do you like any of the names as-is? I don't have a feel for your taste yet.
Some of the obvious variations...
Jean - Gene, Eugenia, Eugenie, Jeanne, John and variations like Sean, Ian, Johanna, Jane
Mary - Rosemary, Mariel, Marian, Marybeth or Mary-Jane (Mary-Jane could technically over Jean as well)
Christina - Christopher, Christian, Christiana, Christabel, Christine, Kristen, Kirsten, Christa
Beatrice - Beatrix, or Bea is a cute one-syllable middle I've seen
Laura - Laurel, Lauren, Laure (Marie-Laure)
Frank - Frances, Francine, Francesca
Irene and Isaac I'm stumped on, other than Irena and Ike.
I like the name Franklin as derived from Frank
Franklin Isaac or Isaac Franklin has a nice ring to it.
Lorelei derived from Laura. As in Lorelei Christine or Lorelei Marie.
You can also do Beatrix instead of Beatrice. I love the name Beatrice but if you're looking to make it a MN i would probably pair it with another classic name.
or you can shorten it to Bea
Jean - Jeanine, Levi (lol, but it could work!), Geneva,
Irene - Francene (nn Frenchie! also honors Frank)
Mary - Marlene (also honoring Irene)
Frank - Fern
Isaac - Zachary, Zachariah, Jacob (Isaac's son)
Beatrice - I'd use this on it's own! maybe Tess
Christina - Corinna
Laura - Laurel, Laurence (nn Lance)
Sorry fir any repeats :)
Jane, Jeanne, Jeanette, Eugenia, Georgina, Gina, Joan
Johan, John, Sean, Seamus, Ian
Renee, Ira(ee-ruh), Rina (ree-nuh), Wren,Irina
Isaac, Ira, Ivan, Renee, Wren
Margaret, Maria, Marie, Marina, Mia, Mariposa, Mae, Marianne, Marianna, Marcy, Mara, Marja, Mina, Magda, Marlowe, Marion, Marietta, Marielle, Marika, Mirella, Marita, Marilla
Mario, Marlon, Mark, Ari, Marcus, Marco, Marcos
GIRLS:Francesca, Fran, Frida
BOYS:Fred, Francesco, Frances, Frans, Franklin
Isa(ee-suh), Ida(ee-duh or eye-duh), Isabella, Isadora, Isabelle, Isabeau, Inca
Beatrix, Beatriz, Bellatrix, Beata(beh-aah-tuh), Bea, Beda(beh-duh), Bianca, Tricia, Patricia, Ryce, Bryce,
Bert, Bart, Bartholomew, Bertil
Christa, Christabelle, Christine, Christianna, Christianne, Chrispina, Kirsti, Kristen, Kirsi, Kirsten, Ristina, Tina, Clementina, Stina, Ina(eena), Chrystal
Christian, Christer, Christopher
Lauretta, Lorelei, Lara, Lorna, Aura, Laurina,Lauren, Laurel, Liana, Lina
BOYS:Lawrence, Lucas, Linus
Jean- Eugenie and Eugenia are favourite of mine, my bff is Li.ly Eugen.ia which i think is beautiful. Jane would make a lovely second middle. Jeanne is a sweet French alternative although maybe is a bit dated. For boys, i actually love Eugene although i know its not fashionable at the moment. Billie Piper's Eugene Pip made me love the name!
Irene- i'd probably go for another name meaning Peace eg Milo, Jonah, Paloma, Serena etc. Or if i wanted a sound-a-like then Iris.
Mary- this has so many variations. Not sure what i'd do for a boy, maybe another Mar name eg Marcus, Mark? Is there a boy's version of Mary?
Frank- i'd be very tempted to use the luscious Francesca if i was naming a girl. For boys, Francis works very well in the middle spot.
Isaac- i love it, i wouldn't want to change it! Maybe i'd use Zack if Isaac was off the table.
Beatrice- see Isaac!
Christina- hmmm, i find this one tricky. Christopher's a good, solid classic but not really my style. For a girl i'd go for Valentina.
Laura- Laura is so pretty, i love it. Lorelei is lovely, but i actually prefer Laura. I'd be tempted by Loretta, Cora, Norah or Flora. I absolutely love Laurie on a boy!
I hope that helps!