Is the New Balance M411LB3 good for walking?

Yes. It is light, cushioned with EVA and has rubber pods for grip, which suits daily walking. It is not a stability shoe, so people needing firm arch support should use their own orthotics.

Can I put orthotics in it?

Yes. The insole is removable, so custom or off-the-shelf orthotics fit inside. Check that the orthotic does not crowd the toe box once inserted.

How does it compare with the New Balance 411 v2 or v3?

The M411LB3 shares the 411 line's light EVA build and removable insole. Later versions tweak the upper and cushioning, so pick the one whose fit and materials you prefer.

Is it a running shoe or a walking shoe?

It is marketed for both. The light weight and EVA cushioning work for casual runs and gym sessions, but it lacks the support and durability for serious distance training.

One pair of trainers with the removable insoles fitted. Laces come already on the shoe.

Does it run true to size?

New Balance athletic shoes generally fit true to size, but try them with the socks and orthotics you plan to use, since the removable insole changes the internal volume.