CATS!!!....upheaval destroyed perfectly good relationships :(((?

I have 3 cats, a 14 year old, 2and a half and 1and a half year old all female. My cats have always got on and have been very loving towards each other until a few weeks ago due to rewiring and getting a new bathroom and kitchen fitted my house was upside down. Tasha my 14 year old has always been a very mothering cat to any kittens we introduced to her despite never having any of her own although she is not spayed she is a house cat, an incident occurred between Tasha and my 2 and a half year old Cleo in my kitchen im not sure what went on but they were both hissing, growling and all bushed up towards each other, Tasha made a run for it into my living-room where Missy the youngest was all stressed out by the sounds coming from the kitchen the results was both Missy and Cleo attacked Tasha it was awful we have never experienced this before poor Tasha wet herself with fright my husband managed to get them separated with his feet, that night we took Tasha into the bedroom with us and separated the other two in different rooms. Since then there has been another inccident but this time between Cleo and Missy but Missy seemed to be the instigator, she is the youngest and is very highly strung and gets traumatised very easily, on the day of the second fight we aloud Tasha and Cleo to come together which was going fine until out of the blue for no apparent reason Missy bushed up and Cleo noticing this reacted accordingly and the fight started this time Tasha managed to get out of the way, once again my husband had to separate them and put them in different rooms, since then we've had another inccident with Cleo going after Tasha but again Missy was the instigator by her behaviour. Today on the advice of a friend we spent �56 on Feliway pheromone deffuser and spray which we have tried, Tasha and Cleo are so mellow but Missy having spent the night in our room came in walking very low to the ground and stepping very cautiously around the room, once she had sniffed the air all over and had a sniff of both cats she has spent the entire day on top of one my kitchen cupboards she hasnt eaten or used her litter box i'm really worried about her and about what we will do if the feliway doesnt resolve this situation it's not fair on her or the other two but it breaks my heart to even consider the possibility that we may have to rehome her, i just cant believe it has come to this after them living in total harmony before. I'd appreciate if you think there is something we are missing or if you have some advice you can give us.