Cleared it with P3 Kerrigan (me) and P2 Tychus in 1st attempt. We were busy leveling prestige last few days due to the warchest is expiring soon.
Didn’t complete the side objective.
Not easy, as they manage to break our bases a few times, but still able to defend the base from destruction and then clear it in the end. Not a clean play, but a win is a win in the end. 
Beat it with Tychus Lone wolf and ally as Abathur P0.
Aba needs to keep placing nests on the ramps so hero waves get some nice extra dmg. Add that with some vipers for CC and they aren’t so dangerous anymore. I kept the reaper in base the entire mission. He had one role and that was to place his charge on the heroes. Some heroes you will one shot with it and all are stunned the entire time. Rest of tychus team was standing in base mainly to provide the buff to Tychus/reaper. Used Tychus to clear the way to the objectives and ally helped out with his bruta’s.
This tactic worked out really well. A thing to keep in mind is to keep both trucks at the same spots and just outside base. This way the truck waves spawn in the same spot. I asked my ally to link his truck to mine and I linked mine to Tychus when clearing bases. This way you avoid those strange and chaotic truck spawns in different places. Both will land in the same place and you can use the odin to completely smash all non-hero units in these wave… for a nerd gasm moment 
For anyone having trouble with this mutation I recommend this tactic. Rerolled one time because of banes/scourge comp but the next time it was bingo ezpz.
HftS is notorious in the fact that it doesn’t scale with the difficulty; heroes are just as hard to take down on Casual as it is on Brutal; the only concessions are that ultimates are not used against you on Normal or lower difficulties. And this is despite the fact that HftS has been reworked again and again (it currently works on a points system to spread out the heroes somewhat, avoiding the issue of Memorable Boss where your armies would need to take down 9 enemy heroes in 2 minutes at the 10-minute mark). And you can say that HftS is still bugged (CtG and Terribleness recently had a video showing how you can “cheese” HftS on Miner Evacuation, due to the fact that HftS doesn’t work properly on that mission, effectively reducing a Brutal+6 to a Brutal+3.)
The advice for lower difficulty HftS clears for a while has “get carried on Brutal”, which may be a problem in and of itself. Again, most mutators scale to game difficulty, but HftS is a notable exception.
It is to be noted that today’s HftS is heavily based on Maguro’s custom mutator idea, titled “The Usual Suspects”. Blizzard has been known to implement Maguro’s ideas wholesale (see the idea of mutator safety zones), and has credited Maguro with many bug fixes. (Some can say that Karax prestiges are based on his “Karax 2.0” rework, though it’s likely that they have been independently developed.) And, of course, Maguro himself has been forever immortalized in co-op lore as well.
Makes you wonder why Blizzard just doesn’t take Maguro’s “The Usual Suspects” wholesale and make that the new HftS.
What really helped me when I struggled early on was a combination of watching howto vids on Youtube and asking for assistance. HftS is clearly broken below Brutal and I’m sure some nice folks on Discord or the forums here would be happy to carry you and/or offer some tips to help you improve. Feel free to open a thread to ask for help.
Vorazun make this game ez. Black Hole is a must and use them only on the enemies hero.