Agree with the advice about sockets - the last thing you want is wires all over the place because your sockets aren't where you need them so think carefully about where you'll have furniture with lamps on etc. If in doubt, put a couple of extra ones in.
When it comes to the kitchen, plan...
No you can't just put the insulation straight over the downlights due to the obvious risks.
There are diy alternatives to the loft caps though; a suitably sized flower/plant pot for example.