#1 - Maria Hill: She has been sketch from the beginning, but she was also significant in recommending Tony take the head position of Shield. (see below)
#2 - Jessica Jones: "Why dont you nurse your baby?" asks Wong...Because she doesnt have the correct equipment, thats why. Luke may be skrull as well, but if its only one of them, she's my pick.
#3 - If Hawkeye was a skrull, it was the one from earlier. BEFORE disassembled. Current Clint is legit.
#4 - Carol Danvers: Why did she insist on her own secret team of shield agents? She's eliminating threats. Also, why does she care about "image"? She is trying to raise her influence to better be a skrull. Expect to see some kind of a tie in with her Kree history.
#5 - Charles Xavier: He has been a skrull for quite some time....
#6 - I predict that sometime AFTER Civil War, Tony either has been replaced by a skrull, will be replaced, or at least an attempt to replace him will be made.
#7 - Dr. Doom will tie in with the skrull invasion. Either HE is a skrull, or Reed Richards is replaced by a skrull and Doom is tied into that story.
#8 - One of the new warriors from Stamford was a Skrull. May very well have been Night Thrasher.
#9 - Namor...Skrull - I wont join the war...Please lead the war for me...Invade. (SKRULL!)
#10 - Pietro. S-K-R-U-L-L.
I thought she was suspicious in the begining and thought maybe it was Mephisto, but, BMB mentioned someone that was really pushing the whole registration. I mean it would be easy to say that one of her kids was killed, vaporized, with their technology it would be easy to fake a birth certificate. Plus they have the ability to hypnotize. So it was probably when everyone was fighting that they were able to sneak on the planet, they probably have been her for some time. Maybe thats wht the Watcher was her for not the Civil War but becasue he was watching them make fools of themselves as the planet was quitely being invaded.