How many miles do your current struts have on them? The reason it's generally advised to change them at the same time is because, in order to install a coil lift, you have to totally disassemble the strut. While you're doing that much work, you may as well put new on generally. KYB struts with OEM Nissan bearings are a very popular and good option as far as that. Rear shocks only take 2 fasteners to change, so it's up to you when to change them, however longer rear shocks will allow you to take advantage of the additional suspension flex lift coils will make possible. In addition, using a nice shock like Bilstein will improve ride greatly.
As far as spacer vs coil, it depends on your intended use of the vehicle, budget, and what you want as far as ride quality. There's a lot more to consider than it seems at the surface. For spacers they will all function the same, so I always recommend Steve's product (sfcreation.com) as he's a long-time member here on the forum and I personally enjoyed his products on my rig. For coils there's two primary options: Old Man Emu or AC. OME (Not to be confused with OEM!) is produced by ARB in Australia and give phenomenal rode quality on and off road, however at less of a lift; right around 1.5". AC will generally ride harsher and may cause your front struts to "top-out" potentially causing them to wear prematurely. However, they provide a true 2" of lift and can take heavier loads better. They're great for a rig laden down with skidplates, rock sliders, and bumpers, or just anybody who doesn't mind a little harder ride who also wants a good amount of lift. My personal recommendation based upon my own experience is a 1" spacer lift paired with OME springs, however this is making out what the R50 platform can take at 2.5" of lift and can make alignment a bit of a PITA. Here's a breakdown of some things to consider:
Spacers:
Good:
-cheap
-simple
-you can add/remove to level out your ride, especially as you change out springs
-maintais factory ride quality
Bad:
-changes the location of the range of motion of the CV's, which means that at full droop they could bind (I can explain this more if you're confused, I may even do a write up on it with diagrams since it tends to confuse newbies!)
-maintain factory ride quality
Springs:
Good:
-stiffer ride/better load carrying capacity
-keeps CV's in stock range of motion (again, I can explain of you'd like) so no binding issues
Bad:
-in some (definitely not all, don't let it scare you!) cases may damage struts
-stiffer ride
-more expensive
Hopefully that's helpful for you. I think it's fairly comprehensive, but it's late and I just got done with 4 days of working on my 4Runner, so I'm tired haha.