Nope, no worries - it is on topic, as it is dealing with the various incarnations of Solaufein, and dealing with them!
The simplest fix for detecting what we want to add to is MOD_IS_INSTALLED. It does expect the mod folder and requested component to remain stable, which *usually* doesn't change over time, but for most mods and modders this is a great way to go. For Crossmod Banter Pack, we are using it to detect materials that have no unique materials to detect, extending existing canonical NPCs without adding something unique and unchangeable
ACTION_IF MOD_IS_INSTALLED ~YOSHIMOROMANCE/YOSHIMOROMANCE.TP2~ ~0~ AND MOD_IS_INSTALLED ~HAERDALISROMANCE/HAERDALISROMANCE.TP2~ ~0~
Unfortunately, if multiple mods are expected to be included/detected/screened out, that means multiple OR and ELSE statements. So we retain old skool "unique items" or "unique .cres" but mostly "do both the dialogue files we add content to both exist", and rely on the banter engine to not call those banters as valid, as it expects the InParty and CD_S_NV to both be true in oder to fire the banter.
So... the only condition under which this might be a problem for another mod is if the added (useless) banters interfere with weighted states in that file. I took a look, and we have no problems. If someone installs a future joinable NPC with "sola" or "solaufein" using the SOLA.dlg we are fine because we do what Roxanne does: check for a banter file and create it if it doesn't exist, and add all our content to that one - if it exists, we toss ours on unweighted. Suprisingly, the only mod that might may need to keep an eye out for install orders is... Roxanne's!
Crossmod is usually a last-after-all-npcs, but Sandrah NPC is a "last of the last of all mods added onto a Mega/BWP install". I don't have a BWP installed right now that even remotely covers the contents in your mod, Roxanne, and my bet is there will still be no issue, but just to check, you might want to peek at the file. Check to see what the weighting is - if it is just random banters you are adding, nothing matters at all, but if you are expecting a quest related dialog being fired off the Baner file instead of the Joined file, then that might be something to look at.
At least you know which mod might be doing something in that file. Worst case scenario, you just weight your materials adding to the banter file to put them at the top of the stack, and make sure thy are fully conditioned, and you are all good.
Thank you for confirming that I did the right thing. So far I have not found any problem with my banters to work nor with blocking off any one elses scripted or random banters this way. "just weight your materials adding to the banter file to put them at the top of the stack, and make sure they are fully conditioned, and you are all good.", (unless there is a mistake in the conditions...).
I needed to take this approach for my own NPCs right from the beginning as their own files are constantly appended by the mods I integrate with. Otherwise Sandrah's own b file which has about 700 state triggers including many chained dialogues would be unmanageable.