Most of the players have been inactive 600 days.
Hello,
no there are no limits. You can stop the game for 1 ou 2 years or more and come back 
Is it a problem ?
No. Boot them or find another alliance, I certainly wouldn’t be in one with various players being inactive for 2 years.
The problem is there is 29 inactive players. One of my account was at war against this Alliance. Someone joined it and noticed it was dead and left so I had to fight a former member, not fun but easy win.