Test in VBox with mem set to 1024MB and 1 cpu.
With ROME LXQt iso 1761 I tried with required RAM 1.0 and Calamares said that was not enough. Tried with required RAM set to 0.8 and installation was successful. System boots and seems to work OK in very brief test.
For LXQt at present user will want to use tiled windows because of bug 2816 until that is fixed.
But this test suggests this is workable on computer with 1024MB. Xfce4 desktop would be another one to consider for this type of application. The isos are available here. User could dual boot LXQt and xfce4!