ADC Resolve .

Yes, it's nice for the most part.

Health regen > 2 damage block > Veteran Scar > Insight

18/12/0 is still ok.

If you don't feel like 50 HP is better than 8% healing / shield with a Karma / Janna / Nami

You can take the other points next to Veteran Scar.

Otherwise for the most part, 50 extra HP is very nice for laning. Could mean life or death in a lvl 2 all in.

All personal preference. The flash / heal CD is pretty nice though. In case you go against someone you need flash up constantly.

No its not worth. The early resolve tree is best for solo lanes where they will matter more. Bot lane is more about farm than going head to head.

You want to fill out ferocity and put the rest of the points into cunning. Early cunning helps you last hit, heal in lane and provides access to dangerous game which is one of the better masteries

I would say probably not, .. but it could be decent on certain champions, and ultimately depends on your personal preference.

I would imagine that the best general combination would probably be

Recovery > Unyielding. Most ADCs don't purchase bonus health, so resistances tend to be inefficient. Recovery is good for allowing you to sustain yourself in lane, but being a tier 1 mastery, this isn't going to make a huge impact.

Explorer > Tough Skin > Siege Master There will definitely be times where you will want to roam to assist a different lane and you don't want to be in neutral territory for very long. Tough Skin will mostly help when taking damage from minions and the support, but you are better off just avoiding that completely. If the enemy ADC is attacking you directly, this 2 damage is not going to amount to much of anything since ADC tends to have a lot of Attack damage, attack speed, and or critical strike chance. Lastly Siege Master is less effective for the same reason as Unyielding.

Runic Armor > Veteran Scars The increased health recovery effect applies to life steal and your base health regeneration, sustain is better for you. +50 bonus health is nothing without some bonus health on top of it.

And since I would expect that you are only putting 12 points into Resolve and 18 in Ferocity, I'm going to stop at this one.

I'll go ahead and say that Fearless is the least advisable because it gives you resistances, ... if you haven't picked up the pattern here there is no hope for you :p

Insight and Perseverance are actually debatable. I want to say Insight is still the better option because your summoners are often very important as the ADC. However, if you are looking for the more persistent safety factor, you can't beat the amount of sustain this offers you, especially with Recovery, and Runic Armor on top of it.

Again though, .. I don't know if this would be any good at all.

Try it out, you may like it.