I know you can't give more than one ability per config for a Warframe using the Helminth system, but I like to compare a Warframe's abilities to similar abilities within the Helminth ability list. This is also by no means a proper rework for Inaros, as the theme is definitely no longer there after this, and that also because the kit design's focus is... bad, to say the least. It's just a very weird playstyle, and it's not even to the most effective level it can be in. If, by any chance, you want to upgrade one of Inaros' abilities, this may give you an idea. So anyways, here's what I think:
Desiccation can be replaced by:
Radial Blind: It just has a larger radius (15m vs 25m), more coverage (cone vs circle around the Warframe), longer duration (8s vs 15s) and also DOESN'T require the enemies to be looking at you in order to blind them. There is also an augment for RB that increases Finisher damage to enemies, increasing Inaros' damage and making his passive more reliable in SP. You however lose the (extremely low) True damage, and the 25% lifesteal that comes with that damage. It also costs 25 more energy, but Hunter Adrenaline exists.
Other alternatives, which are less of a straight upgrade compared to Radial Blind, include: Breach surge (blinds, increases damage, releases sparks on hit/kill, but 25 more energy and NO FINISHERS), Lull (lingering effect that puts enemies to sleep, has finishers, large radius, augment that recasts the ability for free on finisher, but 25 more energy and it takes time for enemies to fall asleep), Rest & Rage (instant sleep, has finishers, augment spreads the effect on kill, but extremely small radius)
Devour can be replaced by:
Blood Altar: Heals Percentage based hp per second, as opposed to 400 hp per second (better for Inaros players with higher health pools), does not lock you (and the victim) in an animation, and heals the whole team at once (it also probably deals better damage, but that point is irrelevant). However you aren't invincible for the duration (but you're still stunlocked). That's.... it.
Gloom: Slows all nearby enemies and grants you and allies in its radius lifesteal (5%). Also drains energy when enemies are in its radius. I think it's pretty self explanatory on why this is way better than Devour.
Other alternatives: Fire blast (only heals with its augment, but also deals damage, procs Fire, and removes armor), Dispensary, Nourish and Well of Life also work but pale in comparison to the other choices.
Sandstorm can be replaced by:
Aquablades: Deals more damage per sec (500 per second on Sandstorm vs 500 per hit, which is 3 hits per 0.5 sec, with a 0.5 sec cooldown in between, and the damage will be increased to 750 soon. Its status chance of slash damage is also 100%), doesn't lock your camera and movement and doesn't drain energy. However, it's range is lower, it doesn't pull in enemies, and it's range cannot be increased by mods.
Larva: Doesn't deal damage but pulls in enemies, bunching them up together better than Sandstorm, and you also aren't the source of the succ. (Ensnare and Airburst are similar in that way too)
Scarab Swarm:
If you're looking for an upgrade to Scarab Swarm's healing, look back at Devour's replacements, and at this point I'm a bit tired of switching between tabs to make precise stat comparisons so I'm just gonna start listing abilities with short explanations. For Status effect removal / blocking:
Molt, Pillage can instantly clear status effects, plus Molt's augment heals you by a significant amount, while Pillage does a little armor and shield stripping.
Firewalker leaves a trail that cleanses yours and ally's status effects. It is also refreshable and the augment is a great burst damage source.
Spellbind gives you a refreshable duration of status immunity, while also providing minor CC.
Hideous Resistance gives you Mesmer Skin-like charges to make you status immune until you use it all up.
If you want armor for whatever reason:
For both:
Defy makes you temporarily invulnerable and turns damage recieved to armor (up to 750. I don't know the math, so idk if it's any better than Scarab Swarm, but at least you don't have to drain 2k hp anymore.)
Honestly, I really just hope DE can see that Inaros needs a complete rework. I know there will be Inaros mains out there that will defend him to the end, but Inaros really feels like pre-rework Wukong. A frame that can't help the mission except "stay alive", which Inaros actually may have trouble in really high levels where the Armor bonus and Arcane Grace isn't enough to save him, since he has no shields or death negation, so he is, in a weird way, worse than old Wukong, yet he is extremely popular, probably due to the outdated Warframe videos on him. Anyways, I hope this goes to show how he needs work, or maybe just give you ideas on how to optimize his kit with Helminth.