Large-Format Poster Design, icon creation -- 2

I have share existing images on Web that must be scaled up or faithfully recreated so they print crisply at custom size (3 feet to 30 feet) for a wall installation. This is for a facility mainly for children (2 yrs - 18 yrs). There are different concepts and themes -
Theme - Concept
1Enchanted Forest - Animals, trees, birds, butterflies
2Space Adventure - Planets, rockets, astronauts
3Underwater World - Ocean, fish, coral, submarines
4Jungle Safari - Friendly animals & exploration
5Fantasy Garden - Fairies, flowers, clouds, butterflies
6Little Explorer - Trains, roads, vehicles, destinations
7Rainbow World - Colours, clouds, characters, positivity

What I need from you:
• High-resolution artwork (minimum 300 dpi at final size) suitable for large-format printing.
• Colour correction and compositing so every piece feels part of one visual story.
• Additionally, i need assistance sourcing or illustrating matching icons or photo elements where originals don’t hold up at scale.
• Suggestions towards colour schemes/ styles

Preferred tools are Photoshop or Illustrator, but I’m open to Procreate or similar if it delivers print-ready files (CMYK, bleed included, layered PSD or AI). Final deliverables will be the print-ready files plus layered masters for any future tweaks.

If you’ve handled poster murals before and can keep fine detail sharp while respecting colour profiles, I’d love to see a quick sample or link to comparable large-format work.