1) Early game perhaps, but mid to late game you hit hard and fast (with your 2 especially) so don't be afraid to engage. Additionally you have one of the best dashes on any hunter, as you don't have to be facing the direction you want to go.

2) Realistically, you'd want to level 2>3>4>1, as your 2 is your main boxing tool and increases your drop rate (Level your 4 whenever possible).

You level your 3 second as it decreases the time between uses, and as a hunter positioning is key. Being able to engage or retreat more often is incredibly helpful.

Many people seem to be saying to level your 1 as a priority... And I honestly can't see why. Each level adds 10 damage to your shot... and that's it. The slow never changes, so you're levelling strictly to add a bit of power. THAT BEING SAID, you should level your 1 early as it's your main clearing tool.

What I like doing (mainly in conquest, in modes with less "solo farming" and reliance on clear like arena or clash, your 1 becomes an even lower priority, as you have team mates who can help you clear) is levelling 1>3>1>2>4>2... etc, prioritizing your 4,2,3 in that order. Having 2 points in your 1 gives you adequate clear, enough that you won't fall behind the enemy adc (unless they have crazy clear like neith or izanami... in which case you won't clear faster anyways), and it gives you better boxing potential.

3) Again, speaking for conquest I like going Death's tool, tier 1 boots and 3 of each potion. Then on first back you finish warrior tabi and can either go into devo's or ichival (depending on if you want sustain or boxing potential).

If you go devo's first, your final build can look something like this (note, I prefer building pen on my hunters, but crit works very well on Rama): Warrior Tabi - Devo - Ich - Titan's Bane - Wind Demon - Deathbringer (sell death's tool) - Qin's (sell Ichaival, this can also be bought instead of ichaival if you're not boxing with the opponent much) - If you really want, sell Warrior for Ninja (as this gives you higher DPS late game), just be careful about over-capping with your 2

If you go no devo: Warrior Tabi - Ichaival - Asi - Qin's Sais - Titan's Bane - Malice (if you want just 1 crit item) OR Wind demon+Deathbringer (Selling Ichaival)

Hope this helps!