The first two seem fine to me, provided the animal can only relay information it itself knows (lay of the land, people passing by etc.). That said, you might have to adjust the agricultural traits of the orcish people; it seems like their hunter-gatherer stereotype would be inhibited by that ability. Even if it doesn't stem from a moralistic standpoint, it doesn't make much sense to eat your informants, or encourage them to be wary of you.
Another suggestion might be something along the lines of invoking the spirits when healing, to give a buff to HD expenditure, possibly for the group. This also pairs nicely with the tales of orc hardiness, and is useful regardless of class/archetype.
The third one seems out of line?
TO me, it seems similar to the first one in power. Perhaps instead of being especially hard to find while camped, the party could roll twice and take the better of any HD spent for healing? Maybe something involving exhaustion? My group hasn't really messed with exhaustion much yet, because we don't really like it, so I don't really know what would work there.
[MENTION=6871653]vincegetorix[/MENTION] I like those variant options. They don't do the thing I'm looking for right now, but I definitely want Half-Orcs to have more options in general, like Half-elves and Tieflings. (Also, Dragonborn have the same need, IMO. GIve me some Draconian variants, at least!)
[MENTION=6802951]Cap'n Kobold[/MENTION] Fair enough, I guess I just have a hard time looking at the half-orc and not seeing an obvious, glaring, problem, so I'm surprised by someone not thinking there even is one.
The option you suggest could work, but it does feel like a pure addition, rather than a variant, and a variant is more in line with how 5e deals with this sort of thing, outside of subrace.
Here is the problem I see, since I didn't do a sufficient job describing it in the OP.
For one thing, I personally think that every race should have a choice of secondary stat increase, even if they don't have a subrace. That part is partly "optimization" based (not really, but I don't feel like describing the distinction between optimization and mechanics focused design), and partly thematic in nature.
Then there are the features. Relentless Endurance is fine. It feels like a purely physical, biological, feature. I'm 100% all for every single Orc and Half-Orc having this feature.
On the other hand, Savage Attacks feels very much like a cultural feature. It fits the FR/generic DnD orc, but less so the Eberron Orc, or a "WoW" esque honorable tribesman orc. At least, it doesn't fit for ALL such orcs to have it.
Further, I like the idea of some orcs being born with a natural proclivity toward shamanism (for me, I'd use either a custom "Primal Spirits" patron warlock or a custom "circle" druid for a shaman. Shaman Druid would use Wild Shape to summon a Spirit Companion, instead of changing shape) or druidry. and that proclivity being represented by a racial trait. I also like the idea of whole tribes/culture of Orc that focuses on such things, and even their warriors have a bit of shaman in them.
I'd love for it to be an ability that isn't about doing more damage, if it ends up being a combat ability. I'd also love for it to be an exploration pillar ability, instead of a combat one.
I'd also love to see a trait that feels more appropriate for city Half-Orcs, while I'm wish-listing.