Yes for final renders. The effects are live Geometry Nodes simulations. Bake them (Physics properties > Simulation Nodes > Bake All), or a final render may show the effect missing or incomplete.

The materials and glow are set up for Eevee. They render in Cycles too, but the look (glow, transparency) is tuned for Eevee.

Yes, in your renders, films and games, under the store's standard licence. You may not resell or redistribute the .blend files.

Yes. Colours live in the materials and in the node group inputs on each modifier.

Yes. The entire collection is built using procedural Geometry Nodes workflows.