wifi cameras and alarm would save alot of faffing about but hard to beat hardwire.
your best bet would be an 8 core alarm cable to each pir point and sounders, keypads, back to were your going to have the alarm panel.
for your cameras its more of what your budget is. can get ones that only need a cat 6 to run, or ones that need a 240v point at them as well, along with harddrive or pc. not my area cameras.
for your solar you will need to allow a low voltage power point in you loft to your boiler and a mains supply for the solar panel. you may need to allow for a stat cable as well.