Im going to credit this to someone on twitter but their was a referrence made to the Batman Animated series ep Perchance to dream and it being possibly used as a hommage in Arrows 100th which I really like and coukd see happening.
For those not familar in the ep a villan creates a dream world that traps Batman and basically tempts him with everything batman thinks he wants-hes parents never died and he never become batman and everything appears perfect. But Batman catches on that there is something wrong with this world and ultimately fights back by choosing to be the Batman because for as much as he loves and misses his parents he ultimately wants his old life as Batman and saving people and having a purpose more.
If Arrow is doing something similar in the 100th it would be a good way to fit into the overall theme of kegacy and moving on. Yes Oliver will have back all his lost loved ones like his parents Laurel Tommy Sara but ultimately he would choose the life he has built now as the Green Arrow over a life with them and therefore show he has moved on. So even if there is some implied OL romance as unpleasent and lets be frank chemistry-less as they would be - and we still have no evidence of that one way or the other- the point will be that Oliver will ultimately REJECT that fake exsistence for his real life. And who is real in his life-Felicity.
Or since the paps said SA was not filming in the mansion maybe KC is filming for LOT
