If you like Hugo what about (la chanson de ...).
Roland
Victor (Hugo...)
Since your first choices are fairly traditional, this should not be too tricky. Most traditional names have a French equivalent. Maybe avoid Irish/Scottish/Welsh names since they will not be as easy to pronounce in French. Some Canadian friends were named Sean/Shawn and found that Québécois friends struggled to pronounce that accurately. Also, anything that starts with H in English will not in French. So Harry/Henry are 'Arrie and Ennree (Henri) They don't really have a W sound either so William becomes Guillaume (Gee yome) and Will is weel
Does it have to sound exactly the same? What if it was Andrew in English but André in French? or Oliver vs. Olivier? Charles vs. Charles (silent S and reduced R to give Shahll or Shahlee = Charlie)
Because Hugo will not sound the same - it will be 'Ugo'. Even if a name looks exactly the same like Ben, there will be slight pronunciation differences.
I'm not pushing the Christian angle here but most Biblical names have equivalents or are nearly the same in all the western languages.
Matthieu
Marc
Luc
Jean (John)
Other French friends of mine:
Eric (ayreek)
Martin
Thomas (hard T 'toma')
Dominic
Paul
Suzanne
Elizabeth (Elisabeth)
Julie(tte) - not Biblical obvs
Lucie
Rose (means the flower and the colour pink)
Maybe try to find a French book of baby names and see how many are similar or if any take your fancy. Surely your OH can advise about what his relatives can pronounce easily and also what might be offensive.
Félicitations! 