Some endgame questions

[SuperNova]

Spoiler

So I have a full dex and defeated Lin. However there is a cutscene apparently that you can get if you have a full dex that I don't know how to get.

 

Also there also is an Anna secret fight I missed as a final boss? 

 

Any help with these? 

 

[Mei-o_Scarlett]

Spoiler

> Upon completing a 100%, 807/807 caught Pokedex in Pokemon Reborn, you receive a special item, that being the Ebony Stonepiece. This item unlocks the door in Citae Astrae,

 

caught

not just seen

if you are at 807 caught tho

you would have recieved the item

 

the anna secret fight is only avaliable on the anna route which u need to do very specific things for that someone else more versed than me can tell u

 

 

[Dred]

Spoiler

Hello
Like stated above, you need to have caught all 807 Pokemon.
Once you've done that, you can go to Bee in Agate City, where you get the previous Dex rewards (Ice Beam, Poipole, etc).
She will give you the Ebony Stonepiece, which you will then bring to Citae Astrae like stated before.