Hi Paul,
Most people go for poly all around. It's easy as it comes in kits. When you read into it, it's strongly recommended to use rubber on the Lower Control Arms (wishbones). I've got poly all around and so do a few people and it seems ok. For my next project, i've got rubber for the lower LCA's based on what i've read.
The way rubber bushings work is a little bit different than what you expect. It's normal to think that the shaft in the bushings rotates, and it kind of does... Poly and delalum bushings are designed to turn a full 360 degrees, acts like a bearing. Rubber though, it's tension, it's not designed to spin freely. The best analogy for this is, hold your arm in front of you, across your body parallel to the floor i.e. holding out your left arm, your left hand should by touching your right arm. That's your shaft. Now your right hand will be the bushing - hold your arm with your right hand,and pretend there's a metal rod between your right elbow and hand. Now, move your right elbow up and down so that your right hand is twisting your left arm. See how you can move your right arm quite a bit, even though your right hand is gripping your left arm, and it's your skin is moving? That's how rubber bushings work - they are constantly in contact and stretching to twist. Poly and delalum on the other hand (no pun intended), you can demonstrate by now loosening the grip of your right hand, so that it glides over your arm, instead of grabbing the skin and twisting. Poly / delalum work like in that way - designed to spin freely. The issues that i've read about with using poly on the lowers, is that it causes binding, as it's not a perfect rotation - it receives sideways forces, creating an angle etc. and when in movement, it could spin freely but then suddenly catch and as it's not like rubber, it won't stretch as easily (as it's not designed to), so would catch and the impact has to be absorbed somewhere, so it would pass it along the chain and put extra load somewhere else and possibly cause deformation of the LCA. Sounds a bit extreme lol but when you read it into that's the kind of stuff that comes up. The LCA's are high load compared to the uppers which is why you could do ploy upper, rubber lower.
Best thing for the rear leaf springs is the Energy suspension full kit, comes with shackles and bolts. I made the mistake of buying just the bushings. What happens is you take the bolts out and realise you don't want to reuse them, if you've managed to remove them without cutting them. Shackles will be pitted and may get damaged when trying to remove the bolts, so you'll likely want to change them once it's sat on the floor and you question the stability of everything
I ended up buying the full kit ($119) after trying to keep the cost down and going just for bushings ($59) but ended up paying 1.5x the full kit cost. Just wanted to share that so you don't make them same mistake as me 
I'm good at making mistakes lol. But if you're going for a completely different setup (coilovers etc) then the kit would come with all bushings etc. Most second gens i've seen over here have leaf's and they get raced too. I'm not sure how much there is to gain with coilovers, i'm sure it's better as modern cars don't have leafs anymore but maybe that's partly a weight thing too. I would say that unless you're autocrossing / racing etc. and are counting to 0.00, then there woudln't be much to gain from a conversion. I would save the money and put it towards keeping it well maintained.
Having said all that though - it's your car so definitely build it the way you want and the way that makes you happy. Sometimes people enjoy modding for the sake of it, so it's ultimately a case of how you want the car to be. There's not much fun in keeping them all the same. I just wanted to share my thoughts and experience but by all means feel free to ignore
and go with what makes you enjoy the car the most. Whatever you decide on let us know, if you go with coilovers would be good to see the conversion process as i don't think anyone on here has done one, would be interesting to see how it all goes together!