No start key/EWS issue, please HELP!

[3ztwint]

Hey guys, have an issue that I REALLY need some input on from someone who is knowledgeable. First off this is on an 01 e53 (X5) 3.0 auto;

The main issue: Original key won't start car after being opened and battery replaced (diamond key), also of note the alarm was triggered (locksmith had to open from wife breaking door lock (before keyless battery replaced, so we were only manual lock/unlocking)). NOW bought NEW key from BMW and it worked for about 5 starts over 2 days now it stopped working (key turns in lock but will not start OR turn over car). Of note here is that I believe it stopped working the first time I locked the car/enabled alarm (used keyless).

NOW I have INPA and I did a scan and EACH key is showing "invalid password" in the error logs. I ALSO have AK90+ and I took out the EWS (EWS3) and used it to reprogram BOTH keys, and after 3 attempts it the keys STILL DO NOT start the car.....

SO, my thoughts are: this is an EWS/Key sync issue and I can either buy a new key from BMW (but it will likely stop working again like the first replacement I bought), OR I can buy a complete e53 EWS/DME/Lock cylinder kit off ebay (see the youtube vid where an x5 fires right up when these are swapped, no programming reqd). I'm just not sure where to go on this one since I don't know if EWS is bad, Key ring antenna is bad (not likely since replacement key fired car up first try and worked each time until the time I locked the car and then would not work again), or could this be an alarm/immobilizer issue?

I'm completely stumped, even with extensive searching, because even WITH AK90, I still can't get the keys I have to work. ANY input would be GREATLY appreciated! Again, the only errors on INPA is "key number 1 not valid because of wrong password" (also "key number 4..." - the new one). Please Please Please help!!