LDoA question

can I still get this if I reach level 20 in pre-sear without EoTN but install it later when I'm in post-sear?

Yes.

12 chars.

thanks. 12 chars?

12 chars because theres a 12 character minimum on posts

The Hall of Monuments (available with Eye of the North) is just a way to document or acknowledge titles and achievements you attain. Different accomplishments have different requirements. The only thing required for Legendary Defender of Ascalon is a Prophecies account with a Prophecies character who attains level 20 before leaving Pre-Searing. Once you've got that title, you can't lose it (unless you delete the character). But once you dedicate the achievement to your Hall of Monuments, the statue will remain in account view (and contribute to your GW2 reward points) as a testament to your achievement, even if you delete the character who dedicated it.