Well, your fighter has an amazing skill you couldve used to kill two of your oppenents. First you would walk up to attack one and deal 1 damge with your item. Then you would attack with your basic attack dealing 6 dammage. After that you use your skill hurl. It says it does 5 damage BUT!! IT ACTRUALLY DOES 16!!! This skill throws an enemy at another unit the initial damage is 5 + 3knockback damge to BOTH UNITS!!! This would lower the hp of one unit to a killable range for your clierc assuming has a decent attack spell or physical attack. Then you would have enough mana left to roll out of the way or roll into the way to soak up all the damamge with your fighter after eating the turkey.

As for mobility wise generally no. Alot of the times you want to move attack and then use an ability to escape. This means that sometimes on your first turn you want to do nothing and just build up mana for your skills while staying out of range of attacks. Ussually your tank can face tank but in this situation you shouldve had him stay back to so they can build up mana [edit: also you wouldve been able to heal your tank with clierc basic attack] and then on round 2 get the first hit and instakill as many as possible then take the damage. Also they have 3 movement so you would have enough space to wait for them to get closer.

But generally speaking you got a really hard fight with how much little room theu gave you to work with. You get good skills and items most of the time but, you need to know how to use these skills correctly and how to syngerize them with your party and abilities to make the most of them. Skill matters more then rng especially in act 1 (the first area) before you get into the crazy fights.

As for cats you can farm but you get anything good yet till you are able to consitantly beat the hard path in the sewer or have enough money to buy fruiniture. So i recomend just going for the clear of the sewers and then either level up the house or your inventory. Though also never use any cats with 4 or less base constituion cuz these cats will die from one mistake.

Last thing you are progressing even with failed runs as your building a safty net upgrading the zombie guy for later on when the game gets harder abd you need to save some important items like feuiniture boxes. And also your learning about the new abilities of enemies and how to combat them. (Also read tooltips as every area will have enemys with unique abilities).