New at Jimny 4x4

Hey guys ,

New a Jimny world, I used to do offroading on rzr but life took me to jimny (wife) so I got some questions, I want to build to do some mild offroading but have some questions you might be able to help.

By the way I am from Mexico so jimny is quite new here but has been a success, so I will be importing mostly all of the items.

This is what I have on my jimny right now.

Current:
HD1 Bull Bar  with 4500 lbs winch
K02 A/T tires but switching for KM3 M/T increasing tyres to 31x10.5
1.5" lift dobinson
6" KC hilites era4 KC lights and Rigid 40" bar
Roof Rack (Aluminum)


Upcoming for water crossings
Non invasive snorkel thefore taking out KC Hilites and relocating era4 KC in its place. lightning if overkill haha.
seals on doors
Diff breathers.
Suspension wise, For now I have the 1.5 lift from dobinson but will change next year for the 3" lift, in this one, 

Questions:
RIms
I will change rims but haven't found 15 inches wich beadlocks also, will I get benefit on -6 or -12 offset rims to widen a little bit the track or should I stick with 0.00 offset? 
perhaps If I do 3" can i go 16inches with same 31x10.5 tyres? has anyone tried this ones.

Gearing & Diff
I have seen people have changed a transfer case reduction gears, sorry my ignorance this is for better acceleration and offsetting bigger tyres? or what is the benefits of the reduction gears? I know in drag racing we use them for faster acceleration but less top speed.

I have seem the ARB air diff lockers, should be worth buying for front and Rear? or only Rear

Suspension, 
Like I mentioned I will change for dobinsons mre 3" with the front and rear Panhards rods and I say Dobinson because ive definately loved the ones I currently have but want a little bit more lift.

Arms
Even though mild offroading will be made there some nice extreme routes but you need flex I saw this guy from Pirate Camp Co that featured:
Quick disconect sway bar, 
2-3" lift front control adjustable radius arms
4 link adjustable Kit for the back

power adders:
Down the road after Ive had some KM in the engine I would like to put a turbo on it, but this is the dream still.

I am sorry so many questions but as I mentioned this is the first time I am building a 4x4 vehicle, rzr and Canams usually have all ready to go on the high trims, so you don't realy have to worry about all this aspects.

Apprecciate all your time and knowledge.