ok first let me comment that Galka are a perfectly fine race for a Ranger.. anybody that flames you knows nothing about rangers in the long run .. the truth of the matter is at later levels Race makes no substantial differance in your Ranger .. only in earlier levels when +agi/+accuracy equipment is not super common
ok I'll answer your questions in a nice organized fashion..
1. Ninjas get dual wield at level 10 not 30 so you'll only have to level ninja to 10 to be able to dual wield archer's knives when they become available to you later in your Ranger career, and no, while dual wielding Archer's Knives is super cool.. its over-kill and not really neccesary .. the best sjob for ranger would be Samurai simply for the tp gain .. since its really the ranger's Weapon Skills that truly sends his/her damage soaring above the rest and a samurai sjob will get you both added tp gain per hit and the ability to meditate every 5 minutes to gain tp EVEN OUT OF COMBAT!! .. as far as nin giving more agi then sam .. this is true .. but its only like 4-6 points at level 70 ... not worth it IMO
2. As far as guns .. yes .. they are more expensive and yes they miss more often .. I speak from my own experience not from rumor or what I hear .. also .. unfortunatley all guns suck until at least level 20 when you can get the lv.20 bullets .. there are lv.1 bullets but guess what .. they are DMG:1 .. haha .. forget it man..
However, Crossbows also require the same skill as Guns, "Marksmanship", and are arguably the cheapest of all the Ranger's methods of ranged damage dealing and certainly the fastest (excluding shortbows which are a waste of time IMO).. so you will have a back up weapon when all the guns out there are just too damn expensive or you haven't reached the lv.20 mark yet when the good bullets start showing up..
Unfortunatley .. I do NOT reccommend Guns .. I wanted to use a gun.. but if you take a look at Eurotys' Bow combined with the best arrows available and the best gun available combined with the best bullets there are .. gun only outdamages it by about 10 or so DMG .. also .. Eurotys' Bow has +20-something ranged damage which might make up that 10point DMG differance all together AND it shoots faster.. the sad but true story
but, dont despair .. I went Ranger anyway and I am loving the sh*t out of it .. the first few levels will be rough as hell .. especially as galka .. you'll miss your Weapon skill 50% of the time or more without your 5 minute recast 1 minute Duration accuracy buff .. and even then you could miss .. it sucks .. you'll have a rough time killing decent challenge sometimes .. and sometimes you'll crush decent challenges .. at lower levels missing 3 times in a row means you are dead .. nothing can save you you'd better have your two hour available.. whether or not you live or die is based on whether on not you land your shot, remember that.. bare with it, trust me.. RNG DOES rock eventually
3. Already answered this .. but by the way .. doesn't matter cause the first gun is level 7 or 8 I can't remember which and it sucks
4. It's ALOT cheaper to craft your own .. do it .. also .. crafting arrows for less and selling them at auction for more is a good money maker later on .. not too many rng want to take the time to learn to craft and would rather shell out that 9,000 gil for 99 silver bullets ... ouch .. oh well .. more money for you ^-^
.. as far as extra tips go
GET AS MUCH +AGI EQUIPMENT AS POSSIBLE!!!!!!!!! .. GET AS MUCH +RANGED ACCURACY EQUIPMENT AS POSSIBLE!!!!!!!!! .. HUNT WITH MEAT MITHKABOBS!!! ALWAYS!!!
At level 16 I have +1agi in my dagger, +1agi in my headgear, +2 agi in my rings, +1agi in my bow, +5ranged accuracy in my necklace, +2 ranged accuracy in my bow, +2 or +3 agi when I eat a meat mithkabob for about 20 minutes and a ranged accuracy passive ability.. I know without these are would be nothing .. learn to equip well .. as I continue to level up I am missing less and less .. I imagine there will come a day when I will never miss again .. I am Hume race btw .. and goodluck to you