I will try to explain more or less what I know about the problems with this manga's publication, excuse my English...
The original publisher (Aqua) closed, so all the publications under it had to stop. The problem is, as far as I know, that even if closed, the right to publish those works still belong to Aqua, even if it doesn't exist anymore (don't know why). So the author couldn't just go to another company and then continue the story from the last chapter. And that's why it took so long for Maiden Rose to restart, she has been all this time looking for a company willing to publish it as a new brand manga without losing the work she had already published. The other options were redo the whole thing again from zero (like a different story) or giving up on it xD so I am very happy she was finally able to make a deal with Ihr Hertz to restart the series from volume 2 on forward with the different name
I would start with the first one:
http://www.mangago.zone/read-manga/hyakujitsu_no_bara/
And then all the chibi djs that are canon (official events that happened in the story but were/are not shown in the official manga. These are important because many times they go back at them in the official manga and it can very confusing if you don't know what are they taking about):
-Luckenwalde:
http://www.mangago.zone/read-manga/hyakujitsu_no_bara_dj_luckenwalde_no_heya_de/
-Dawn chorus:
https://myreadingmanga.info/inariya-fusanosuke-maiden-rose-dj-dawn-chorus-eng/
https://myreadingmanga.info/inariya-fusanosuke-maiden-rose-dj-dawn-chorus-4-eng/
Also, you can go to Myreadingmanga and read many other Maiden Rose djs that I don't really want to write down, there are too many:
https://myreadingmanga.info/tag/the-red-cat-brigadeinariya-fusanosuke/
Why was the sequel getting scanlated while the first story is in scanlation hiatus bin? Or is this a remake. Am I missing something? not gonna read this for a while and look for more info #-.-)