Mul for a PC. Balanced? Flavorful enough?

[hellgrammite]

A PC requested the chance to be a Mul for a 5e game, and I wanted to try and create something that was balanced but flavorful. Wanted to get feedback. Thanks.

Mul

Ability score increases: Constitution +2, Strength +1

Darkvision - 60ft

Size - Medium

Bred to Work - You count as one size larger when determining your carrying capacity and the weight you
can push, drag, or lift.

Vitality - At the end of a short rest, you may reduce an exhaustion level you have by one.
After you use this trait, you can’t use it again until you finish long rest.

Resiliant - You gain the benefits of a long rest in 6 hours instead of 8.
In addition, at the end of a long rest, you regain all of your spent hit dice, instead of the normal half.

Resolute - Whenever you make a Strength or Constitution saving throw or a saving throw against being incapacitated, paralyzed, or stunned , you may spend a Hit Die without gaining hit points. If you do, you have advantage on the saving throw.

Languages - Dwarven and Common

[rudy]

I like it. The resting thing could be anywhere from "meh" to "critical" depending on the availability of magical healing.

Also makes Berserker Barbarians actually playable with the exhaustion thing.

[Vlos]

I like, I think the last ability "Resolute" needs a bit clearer wording.

[Ziegander]

Looks balanced and flavorful to me, I really like it! Resolute seems perfectly clear.

[hellgrammite]

Thanks for feedback. After talking over with my local playgroup as well, I made a few changes, notably to add some features to note the harsh battle nature that Muls face (slave labor/gladiator fighting) is pretty much their existence. The gladiator/pit fighter trait emphasizes their effectiveness with little to no weaponry.

Mul

Ability score increases: Constitution +2, Strength +1

Darkvision - 60ft

Size - Medium

Dwarven Stoutness - You count as one size larger when determining your carrying capacity and the weight you
can push, drag, or lift.

Vitality - Whenever you would gain a level of exhaustion, you may instead immediately expend a hit dice
without gaining hit points. If you do, this instance of exhaustion ends. This feature does not work on exhaustion
caused by a lack of food or water.

Tireless - At the end of a long rest, you regain all of your spent hit dice, instead of the normal half.

Gladiator Pit Training - You have proficient in improvised weapons, unarmed strikes and a martial weapon of you choice.
Your unarmed strike deals a d4 for damage. In addition, whenever you have advantage against an adjacent creature, you can attempt
to grapple it as a free-action if you have a free-hand.

Languages - Dwarven and Common