Using Scamper Heals allies within 25 units and you for 600 over 3s.
Gain 6-30% Lifesteal against enemies with the maximum number of Magic Marks.
Increase the Healing you receive by 7-35% while at or below 50% Health.
Reduce your active Cooldowns by 10-50% after getting an Elimination.
Increase your maximum Health by 50-250.
Reduce the Cooldown of Scamper by 0.4-2s.
Disclaimer: I LOVE Moji, always have, and I sourly miss the bygone days when she wasn't arguably the worst flank (and possibly worst overall character) in the game. This is why I've dedicated so much time and energy to making this build to hopefully hold all the other Moji lovers over through this dark time until she (probably won't ever) gets the re-work she deserves.
Reasoning: I picked "Toot" over the newly buffed "Snack Attack" primarily because it's still more reliable and convenient than the aforementioned snack talent. After playing several hours with "Snack Attack" I found its biggest weakness was that the health pack it dropped would often lure you out into a vulnerable spot that would get you almost immediately killed (or at least cause you to lose all the health the pack just gave you) when with toot you can focus on the next enemy and use "Toot" to immediately get back a sizable chunk of health (a chunk that so long as you're below 50% health is increased by 35% by "Symbiotic" to 810)
Cards: "Greater Good" 5 and "Symbiotic" 5 are the biggest part of this build as they are what sustain you when flanking while out of range of your party's healers. In most cases when I found myself using these in 1v1s I most often came on top except when the enemy has "Cauterize' 3. They both affect each other as well because if you have a full stack of marks on an enemy when you detonate it and you are at or below 50% the 35% increased healing will apply to your lifesteal (I've tested it). Meaning if you have "greater Good" 5, and "Life Rip" 3, with "Symbiotic" 5 then when you set a full stack of 10 then you heal a whopping 810. "Peppy" 3 is also a very good card to run because after every elim you shave off 30% of all of your cooldowns. This reset is essential when you find yourself in very chaotic engagements with more than one assailant. "Fluffy"1 and "Scoot" 1 are filler cards that have very good synergy with "Symbiotic" and "Toot" so I recommend them for that slight edge, although they are easily replaceable with something more your style.
Items: Cauterize, Life Rip, and Nimble. "Cauterize" helps you kill stuff faster than it can kill you, "Life rip" stacks with your two primary cards, and "Nimble" helps you land your ult more and position yourself better. For your last item, I recommend "Blast Shields", "Haven", or "Resilience" depending on the situation.
I hope this helps.