I found an article about the Alimo bike operation a few years ago but I can't find it any more, you are probably right, the bikes are all so different.While some Alimo bikes use rebranded Benotto frames, I suspect some others were acquired via Union, or their suppliers.
The burgundy Alimo Nuovo is an identical twin of the Union Sapporo.
This is the Sapporo, with a Japanese frame, made by Miki: