WTB: 24" wheels, V brakes, 50mm stem, other bits for Islabikes renovation

My youngest is moving up a bike size and after some thought we're going to keep his brother's old Islabike Beinn 24 rather than buy and sell — but sort out some manky bits and improve the bike in the process.

I'm looking for:

• 24" wheelset to replace the knackered Islabikes one — for rim brakes
  
• 24" tyres, something smooth-ish and light like Maxxis Torch; ideally similar width (1.75 / 47mm)
  
• 8spd trigger shifter
  
• V brakes — something better than no-name / tektro basics that came with the bike
  
• 50mm 31.8 stem
  
• potentially also a junior crankset (140mm cranks) — one of the junior BMX ones perhaps. Something that'd allow fitting regular chainrings rather than the bolt-on proprietary Islabikes (rubbish) one. I have a 104BCD ring which would fit so that size would work and seems to be the BMX standard.
  
  

Looking at that list I wonder if it's a bit crazy as there's no much left of the original bike! But if I can find things at reasonable enough prices and make it a bit better in the process it'd work well. And we might try out spray.bike to really pimp it too.

If nothing shows up I'll maybe reconsider but if you have anything lying around from kids' or BMX builds that you think would do the job, I'd love to hear more...

All would need posting as I'm in Newcastle.