Not kids related but I am on public transportation 4 hours/day so I care about feeling hot on my laps.
2018 MBP 13" i5/16/512 does get hot after normal browser, emails, iMessage use. Then again it's 30 Celsius in my apartment but I'm in my living room with the 10K BTU A/C going at medium. Outside is roughly 26 Celsius. Mine is ok for lap using light shorts on the couch ... but if I queued up GarageBand or Xcode or anything that demands more resources ... then YES it gets TOO hot.
- I never use Safari full screen
- I do use iTunes full screen on a dedicated space.
- LOVE the TouchBar ... very convenient for tedious tasks.
To me at quad core i5 it's VERY close to the performance of the same on an i7: for usual typical mundane tasks. MS Office suite doesn't really care if you have an i3/i5/i7 ... these Intel chips are not ramped up for single threaded apps.
GO with what works best for YOU!
Start with your existing machine ~ I din't have a full working laptop/no PC for months. My MBA 2011 needed LCD backlight repairs which took a week thus I ordered my machine prior for that repair to being.
isolate what your needs are:
in terms of applications, power, size then weight.
* ensure you have the adapters you require.
Ensure you have a case or skin and a GOOD bag to use your Mac in.