I don't think remaking the Old Ones Language is even close to those other projects.
The languages one step removed from the Old One's Tongue are:
- High Nehekaran: Mathilde can learn it written or spoken for 1 AP, so at most learning it will be 2 AP.
- Arcane Khazalid: We can learn it now and if we're successful with the Sevirscope we might even be able to get Kragg to teach it to us, emphasis on the "might". Most likely we will just need 1-2AP to learn it.
- Grumbrath: The language of Ogres is also 1 step removed from the Old One's Tongue. We can learn it at the Colleges. Most likely we will just need 2-3AP to learn it.
- Saurian: unlikely we can learn it unless we can get it from the Asur note, the White Tower or the Druchii (and even then I am not sure those 2 would have a lexicon).
- Albionese: unlikely to learn unless we wait until 2518-2519 when the mists start to fall, and that is assuming they start to fall.
- Anoqeyån: we could try to make a deal with someone in Tor Lithanel to learn it, in fact, we could even try to get classes on it for the Colleges in exchange for the Fog Path. I feel because of its completely it'll most likely take Mathilde 2-3AP to learn it
So what do we have? That it would take Mathilde around 10 AP or less to learn all the languages she can that are one step removed from the Old Ones.
After learning those we'd most likely just need to take the action to try to reconstruct the language.
So although it'd most likely take us a long time to do so, it'll be because we focus on other things instead of because it's something "super long term" by nature like Ulgu Ascension.