Welcome to KI, I hope you’re enjoying the game.
I’ve been maining Tusk since he was released, I’m not pro by any means, but I like to think I’m half decent at least jaja. First of all, you need to understand Tusk’s game plan; he doesn’t have any difficult to react mix ups outside instinct (and even then you won’t be able to get more than one or two full combos per instinct), and he also doesn’t have any crazy gimmicks to open your opponents up, so your damage is going to come mostly through solid fundamentals, punishing unsafe stuff, baiting throws, mid range pressure, good anti airs and good use of your deflection windows. In a way, playing Tusk is like playing some traditional street fighter instead of killer instinct, so be patient and don’t panic if your opponents get an early life lead, sometimes one or two mistakes from them its all you’re gonna need to win, since Tusk has one of the best damage outputs in the game.
About the MU you asked for:
Sadira: As already mentioned, trying to keep her grounded is key, which is easier said than done. cr HP is really good against her left to right mix ups (sometimes even they don’t know which side they’re gonna hit you jaja). Also use your DPs and st HP depending on how they jump. Once you knock her down, keep up the pressure with short combos, using your hard knockdown and stagger ender, Sadira doesn’t have any truly invincible moves (her shadow backflip is only upper body invincible and needs meter of course), so be ready to use meaty cr MK, grabs and neutral jumps on her wakeup. She doesn’t have any grounded overheads either, which means you should always use crouching guard while she’s on the ground.
Sabrewulf: His damage and mix ups are not as scary as they used to be, but he is still viable, specially with the buffs he recently got. However, he needs to get in to do any meaningful damage, so keep him away with your best pokes; st MK, st HK, cr mK, cr MP and sometimes st MP. Once you land a couple of combos, be sure to use your hard knockdown and stagger enders as well and keep up the pressure. Be wary of wulf resources though, he has access to an invincible uppercut if he has meter.
Shadow Jago: Resource management is key for shago players, they have to choose to either use his meter to make his offensive safe by using surge, or to do any meaningful damage, so pay attention at how they play and react accordingly. If they use meter to damage, that basically means every opener is going to be VERY unsafe on block, you can punish his dive kick with st MK or st HK and follow up with any combo of your choice. His slide kick can be punished with a grab, which leads to a hard knockdown, giving you a free setup. If they use meter for surge, then all you need to do is to wait until they run out of resources and start your attack, even if that means eating a couple of combos, since the damage is gonna be low anyway. If they try to zone you with fireballs, you can punish them with collateral damage or a good jump in with MP. Remember, Shago has an invincible uppercut, so don’t jump like crazy or keep pressing buttons on his wake up, sometimes bating an uppercut is better than pressing any buttons, the risk is very low (you only lose some momentum) and the reward can be very high (a full punish).
Orchid: Pretty much like wulf, she needs to get in to do any damage, so use your pokes properly. As already mentioned, her slide is punishable with crouching jabs or with throws, with the exception of the shadow version. Her low and overhead rekkas are also punishable, so be ready to block or shadow counter accordingly. However, unlike wulf, she does have a proper, fully invincible DP that doesn’t require any meter, so you have to respect that and punish it on block/whiff.
Mira: She has relatively poor anti air options, and Tusk’s j MP has fantastic range and you can combo out of it. If you time your attacks correctly, you will hit her while she’s still on recovery, and you won’t have to worry about the bats, since they go away on hit. You can also try yo use inmortal spirit to try do down profile her projectiles, but use it sparingly, because you may get punished if she hits you with her slide. In this specific battle it is better to save your meter for shadow counters, since her mixups are almost impossible tor react. Also, try to not use your slower normals very often, she can teleport and punish you.
Rash: When he’s in the air, use the same tactics that I mentioned in the Sadira MU. Additionally, You can deflect his wrecking ball on reaction using st HP if he uses it from full screen, so go to the lab practice it. Last but not least, a lot his stuff is actually punishable with grabs or jabs, so be ready to react and punish.