What do you mean by a "sight" ? Do you mean the camera or the reticle within the cockpit? The camera definitely has IR.
Similarly, I've never had the issue you describe with the laser. The 18 does have a much narrower angle with which to spot the laser, maybe try to make sure you're approaching the target head on at a proper angle. This would be an especially big shift for individuals who only use the APKWS missiles which are overpowered and essentially able to turn on a dime. I recommend not using those and instead learning how to use bombs like the GBU-12 if that's the issue.
The pylon losing loadout thing is well documented. You just need to double check that the loadout is really loaded before takeoff, there isn't any fix I've found.
FWIW, we swapped to the 18 because the "amazingly easy" maneuverability of the F35 is incredibly overpowered. The AV8 was likewise very overpowered, although admittedly less so as the AV8 is just slower and lacks the organic stealth stat of the 35.
The F-18 mod we use is more challenging sure if you only used the other aircraft as overpowered death machines, but it's more fun too if you know what you're doing.