So as the matchmaking got worse for some reason (always getting solo fireteam). I decided to take the challenge and play a solo full stealth gameplay fireteam, got surprised that it was actually really fun. BUT it has some issues that i want to adress wich breaks the stealth strategy for no reason:
1.- The Predator can attack the AI base that of course, will trigger the alarm, no problem there. The problem is that the AI will persue the FT instead of the Predator that triggered the alarm, knowing the exact location of the FT player that was perfectly hiding and doing the favor to pinpoint the Predator where the target is. Solution is kinda obvius, if the Predator triggers the alarm, the AI persues ONLY the Predator IF they dont know about the FT presence.
2.- Some missions trigger the Alarm so its a matter of luck if you can make a complete stealth run. I hope devs can add the option to make the AI in an alerted state instead and start looking where the FT is instead of knowing exactly where player is.
3.- Finally the extraction WILL trigger the alarm. NO PROBLEMS THERE, i mean, is a god damn flare that is calling a really noisy helicopter. The problem is again, the AI knows EXACTLY where the player is, pinpointing the position for the Predator. Make the AI to get to the extraction flare and from there to start looking for any movement/noise. This will make the predator to know where the FT may be extracting, but not where the FT is, also as the AI will be there too so it will distract the Predator making an opening for the FT to act.
So, to summarize:
-The AI will track the Predator if he triggers the alarm, but also will track both the Predator and the FT if the AI also knows of the FT presence.
-The AI in the alerted state will search the area based on movement/noise.

