1) Yes, they have their differences and both are good. Sense type characters have 3 paths: gunner (AC), thrower (DA) and thrower wt (WT). WT is uncommon but good for afk drilling.
But to focus your character on drilling and compounding the thrower path Fox is easier.
2) 3142: some peoples use for gunner path (pros: more AC = more dmg with gun / Cons: less def and hp.) it's worthless use for thrower path since is DA Based.
2143: standard and balanced stats for any paths. (pros: balanced gun dmg and defense)
1144: is the best for veteran players for any paths. (Pros: High def and hp / Cons: it's difficult for gunner begginer with low gun damage.)
- Invincible Drill (you must have for a good drilling)
- Sixth Sense: Lv10 or Master (main buff for increases your damage skills)
- Stone Strike: Lv10 or Master (main damage skill)
- Heavy Carrier: Lv10 or Master (Optional but it's worth a extra weight limit)
- Shuriken Master: Lv10 or Master(damage skill)
- Armor Destructor: Lv1 (req. for Lucky Seven)
- Lucky Seven: Lv10 or Master (buff to increases LK to help in-game compound, refining and also increases damage of some skills)
- Anger Management: Lv.10 or Master ( If you dig manually this skill help you increase crazy drill gauge faster. For auto (afk) drilling is worthless)
- Compound Master: Lv.10 or Master ( for in-game compound you must learn but, for web compound has no effect)
- Precise Pitch: Lv.Master (this skill is optional to learn Fan of Knives and Rain of Knives for extra offensive skills)
- Item Detector: Lv.10 or Master (If you dig maually this skill will save your time and stess, for auto (afk) drilling is worthless)
- Aura of Luck: Lv.10 or Master (More extra buff to increase LK)
- Chain of Knives: Lv.10 or Master (optional and very good skill for offensive)
- Mega Crazy Drilling: Lv.10 or Master (If you dig manually this skill will increases crazy drill effect duration. For auto (afk) drilling is worthless)
- Fan of Knives: Lv.10 or Master (optional but if you need a AoE Skill, I recommend)
- Rain of Knives:Lv.10 or Master (this is optional AoE Skill too but, just have Fan of Knives is enough)
3rd Job Skills: all fox 3rd job skills are offensive skills.
4) for afk drilling: any equipment which contains LK HP and High DP and MD as possible. Any refined shield: altiverse, legendary or requiem.
Conclusion: To afk drilling you just need hight HP, DP, MD, WT and min. 90DA. No Skills need to learn for support except Heavy Carrier.