Shireneko
You can make small time skips but not much because that can ruin the story progress as for the fairy island accidant where everbody stuck for 7 years if mcâs lovers ( mira, erza and others) gonna stuck their mc should stuck too in that island but you can make them defeat or escape the island because there is now mc and others are stronger than in the canon.
after all cast+ur(if possible) joins.....I think you should create a few chapters to cultivate their relationship (between mc and the girls) even if not to the point of romantic but still considering each other important (more than others).....use in between event like healing erza's eye, saving lisana ,a few combined mission with mc and the girls helping the girls increase their strength (specially Cana.... since she use card magic you can take reference from you gi oh.... like the more rules she set the powerful she can use ex- setting up field or being in particular environment....or a specific card can only be used at specific time of day... like cruel sun when used only at peak high sun the more powerful it is...or enchantment cards.. like talisman).....you can even connect the dark mages that tortured him to tower of heaven this a good reason to for connection with erza.... going for time skips without proper foundation for the future relationship would decrease romance effect in the herem....as for tenrojima 7 year skip....I think instead of sealing him with others.. ... have him some how escape and work on his statue and husie relationship (if you are going to include her)....ex having him going on rampage killing dark guilds as grimore heart was one of the reasons..... increase his strength to kill acnolgia and husie helping him and healing his broken heart ...you can also connect the statue with the curse the God gave to zerif and Mavis ....and lot more.... HOPE IT HELPS EVEN A LITTLE THANKS FOR THE CHAPTER đđđ