Thank you very much for your suggestions
I am French and play in French, but if the Empire is intended to have Germanic feels, including in its language, then I like to do it well and to use as correct as possible German. Even Early New High German if possible, but I've yet to find an online grammar for it, in French or English... I think it might be silly
and correct
and archaïc

. Like Warhammer Fantasy designers, I alas do not speak German, but as German publishers did feel they had to correct Imperial names, I get that they undoubtedly know better than English designers (just like I can see how French publishers were right to correct Bretonnian names).
Zisse, would you think you might share with us German version of the Imperial calendar (or just give me names of months, week-days, epagomenic days, satellites names) ?
In my calendar rough booklet, I did use this terminology:
For planets and the star:
Imperial name (Eltharin name) - associated Imperial god:
Söllsfiur (Asuryan) - Söll, Dhaz
Rhyanleib (Gia) - Rhya
Mannslieb (P’hílêmathlaños) - Mannan
Mórrslieb (P’hílêsarrielos) - Mórr
Händrichskupferpfenning (Charyb) - Händrich
Lichtbringer Morgendämerung (Deiamol before aurora) - Shallya (the duality of this planet is a reference to Venus)
Lichtbringer Abend (Deiamol after twilight) - Ranald (ref. to Venus)
Ulrichsrotwolf (Tigris) - Ulric
[Something related to Verena?] (Verdra) - [Verena ?]
Kháinesherz (Lokratia) - Kháine
Ishernanleib (Isherna) - Ishea
Others planets are either unknown (Loekia, Voelia) or contested (Obscuria) by Westerners...
Day names:
Like in the Germanic timekeeping, days are divided into nights (divided in twelve relative hours) and daytime (divided in twelve relative hours), in that order.
As night come before daytime in the Ancient Germanic culture, and during a part of the Mediaeval era, I presume (but I may be wrong) it explain why Sonnabend might had been used for the evening between Sonntag and Samstag before being used for the whole Samstag in the area of Cologne.
In the Anglo-Saxon calendar, the night between Sæternesdæg and Sunnandæg was Sunnanniht.
night - daytime :
Neumannslieb - Kalend
Werknacht - Werktag
Fronnacht - Frontag
Marktnacht - Markttag
Bäckernacht - Bäckertag
Bezahlnacht - Bezahltag
Königsnacht - Königsttag
[?] - Frühwoch
Festnacht - Festtag [or Hexensnacht - Hexenstag the 17th day of Hexensmanoth ; or Geheimnissesnacht - Geheimnissestag the 17th day of Geheimnissesmanoth]
[?] - Mittfrühl (spring equinox day)
[?] - Söllenstill (summer söllstice day)
[?] - Mittherbst (autumn equinox day)
[?] - Mondstill [Mondestill if we count the two satellites? or Mannsliebstill?] (winter söllstice day)
Months names
#. name (event: date)
I. Hexensmanoth (periastron: Königsttag 3. Vorhexensnacht?; Neujahrstag: Hexenstag )
II. Hornung (Lenz: Iden des Hornung)
III. Jahrwend
//Mittfrühl (Frühlingspunkt)
IV. Pflugzeit
V. Sigmarzeit (Sommer: Iden des Sigmarzeit)
VI. Sommerzeit
//Söllenstill (Sommersöllenwende)
VII. Geheimnissesmanoth (Apoastron: Königsttag 3. Vorgeheimnissesnacht?; Neusemesterstag: Geheimnissestag)
VIII. Heumanoth (Herbst: Iden des Heumanoth)
IX. Erntezeit
//Mittherbst (Herbstpunkt)
X. Brauzeit
XI. Kaltzeit (Wintar: Iden des Kaltzeit)
XII. Ulriczeit
//Mondstill [Mondetill? Mannsliebstill?] (Wintarsöllenwende)
Veniam, Duelli Malleum, phantasticum ludum personae uidebo, in fera terra periculosorum aduenturorum ludebam.