4*+20 does add HP, and DEF, to Jackal. Even if you choose 100% attack path.
But a yellow Jackal 4* 4.70 has less defense than blue Gunnar 3* 3.50 , as much as blue Grimm 4* 4.70, a tiny bit more than red Scarlett 4* 4.70 ( see notes ).
Pack
I agree.
I did say Jackal / Valeria are great in duplicate.