Get in close at beginning,
most of aliens moves are less useful up close due to them being 14-30 frames of startup.
besides B1 and 1 starters being 9 frames or lower on startup.
but all the scary ones like
F+23434 = 12 frames of startup
B34 (low low) = 18 frames of startup
F34 (mid OH) = 21 frames of startup
333 = 12 frames of startup
F4 = 17 frames of startup
so my tip would be to stay close, and check him with moves below 12 frames.
you will still have to watch out for
B113/B11BF4 = 9 frame startup
12 (high low)= 8 frame startup
1 = being +1 on block
B1= being plus 2 on block
112 can go into EX crawl combo
123 can go into 50/50 setup
but as you can see when Alien is mid range, he has alot more options just from his normals.
so closing that gap cuts half of those away assuming you play very agressive and constantly Button check him with fast strings/Pokes into full combo punishes.
as for his EXO Sting(DB2) zoning and his Sizzle Strike (U+3)
its a guess game for him and you both.
if he guesses wrong you get in. if he guesses right he keeps you out.
if they do 2 EXO's then Sizzle Strike then run in after the 2 Exo Sting's
if they do 1 exo sting then Acid blood to keep you from running in alot, run cancel into a jip after the first exo sting..
its all a guess. but be ware, jump ins can be Reacted with Sizzle strike anti air (U+3)
however you get in, stay in and you should be able to keep in.
id use a character with either projectiles that are Fast, or a teleport character, or one that can fade through them like Ethereal Mileena. and someone who has great pressure up close like, Kung Lao, Sektor, Mileena, Sonya, Cyber sub Zero, Kano.
Kung Lao, Kano, Sonya, and CSZ have a dive kick type move that can be used to counter zoning.
Mileena and sektor have multiple moves to counter zoning = Fade(mileena) tele kick(mileena) and Sektor has knockdown with forward rocket, and Teleport uppercut.
unless you are a zoning character.
then keep him out, cuz you can win that with many zoners like Kitana, Kano, Jacqui, HQT and Liu