Electrical advice for a new house

Hi everyone,

First time poster so please be nice

My fiance and I are building in Perth for the first time and are a bit unsure of some of the stuff for our electrical plan. So in short what we like is for the whole house to have downlights installed over handover. So we have chosen to switch most of the standard lights provided to a junction box instead. But we do have a few questions on a few other things:

1) Can a JB control two sets of lights separately? For example, if we have 4 downlights conencted to a single JB, is it possible for us to have 2 switches for that JB, 1 switch controlling 2 of the lights and another switch for the other two. If this is possible, what would I need to specify with my builder to get it done?

2) I spoke to an electrician and he suggested us to get conduits throughout the entire house. So I'm not too sure what a conduit do. I know it is for allowing the ease of multiple wires to run from multiple JBs/lights to a single point on a wall with lots of switch plates. But is there a need for conduit throughout the whole house? (especially when I will only have two downlights lights for most rooms?

3) Regarding external lighting, do you suggest us having 4 weatherproof JBs for each side of the house? (so one JB for all the lights for a single side) We would like to have flood lights and sensor lights eventually installed for the external of the house but I'm not too sure whether 4 JBs are actually needed or just a single one.

4) We are building on a rear block (battleaxe) so we would like an electric gate eventually somewhere along the driveway. Do we require a JB for it? Or should an external powerpoint be enough?

Thanks a lot first for all your replies.
We are very new to building so do apologize for the naivety in some of the questions.

1 - yes. We have this in our house.

2_ its good idea to get conduits anywhere you might have two light switch plates on the wall, or maybe in the future you install a fan you'll need a conduit for the slraky to be able to run a cable down the wall to the switch plate. Or if you want dial dimmers they run on two cables ( unless you get the push ones which only need one wire). Basically a 25mm conduit gives you contingency to get what you want electrical wise on internal walls where there is no cavity, or even on cavity walls where it might be difficult to run wires down because insulation and ** brickwork or excess mortar gets left in the cavity making it difficult to feed a cable through
3- our builder wouldn't do weatherproof junction boxes so we had one put in our alfresco and front of house for our garden lighting
4_ suggest you speak to a company that installs electric Gates and ask them