I don't understand why they made these episodes, it isn't a prequel (I'm watching the first one atm) so what was the point of it? And they were going to release this next season? Kind of shows the problem with the show i.e. they make too much filler to pad things out after they do any sort of reveal. Also their production/release schedule was always terrible with 2 episodes in then 2 weeks break several times in a season.
Lucifer did have decent numbers so I don't know why it got cancelled but even if it doesn't get picked up I'm fine with it because I wasn't invested in the show as much as I was in The Expanse which I'm glad got saved by amazon itself and now that show is in a much better place than it ever was before.
The problem is Fox more than the producers, if you ask me. Back with season 2, the season was only going to be short but they ordered more episodes. Unfortunately Fox decided they couldn't schedule 6 of them iirc. Some of them already got shown in Season 3, hence why we got quite a few odd episodes which didn't fit in the timeline. I was under the impression these 2 were part of that as well, but again was cut due to scheduling.
I don't think we can really blame producers for all of these scheduling issues, really.
As for why it got cancelled, Fox seems to be rebranding itself. Their upfront was all about "New Fox", which involves them having gotten the rights to air american football and wrestling which is taking up two nights of their scheduling now. Lucifer got cut for that. =/ Not going to lie, as someone who isn't American, I'm kind of bewildered why they don't have a dedicated sports channel for that stuff, but what do I know I guess.