Problems, and need info for 1990 BMW 325i

If it matters, the car is a 2 door convertable.  I have a few different things I need help with...

The door locks are frozen, you can't open the car with the key, so it's just left unlocked all the time.  I'm not familiar with BMW's, and don't know if there's anything special about them when removing door panels, any info would be great.

It has a factory alarm.  Any way to keep this and use a remote start?  Anything unusual about installing a remote start on this car?

I won't be looking at the car until tomorrow, but I figured I'd try to get a heads up before I started.  Any info that could save me from anything unexpected would be appreciated.

|       ITEM      |     WIRE COLOR     |POL|       WIRE LOCATION        |
|              12V|red                 |+  |ignition harness            |
|          STARTER|BLACK / YELLOW        |+  |ignition harness            |
|         IGNITION|green               |+  |ignition harness            |
|  SECOND IGNITION|purple              |+  |ignition harness            |
|       POWER LOCK|yellow/blue         |-  |drivers kick *1             |
|     POWER UNLOCK|GREEN/ blue          |-  |drivers kick *1             |
| PARKING LIGHTS +|gry/wht and gry/yel |   |light switch                |
| PARKING LIGHTS -|                    |   |                            |
|       HEADLIGHTS|YELLOW /GREEN        |-  |light switch                |
|     DOOR TRIGGER|BROWN / purple        |-  |dome delay relay dkp        |
|  TRUNK/HATCH PIN|BROWN / black *2      |-  |at trunk light              |
|  FCTRY ALARM ARM|                    |   |                            |
|FCTRY ALRM DISARM|                    |   |                            |
|       TACHOMETER|black               |   |diagnostic connector        |
|       BRAKE WIRE|GREEN/ red           |+  |brake switch                |
|     HORN TRIGGER|BROWN / yellow        |-  |steering column             |
|           WIPERS|blk/red             |-  |wiper switch                |
|  LF WINDOW UP/DN|black - purple      |A  |center console switch       |
|  RF WINDOW UP/DN|blk/gry - pur/gry   |A  |center console switch       |
|  LR WINDOW UP/DN|bul/grn - blk/yel   |A  |center console switch       |
|  RR WINDOW UP/DN|brn/grn - blk/yel   |A  |center console switch       |

Notes:*1 Remove drivers kick panel speaker, remove plastic cover below speaker, remove the two screws to pull relays. Keep relays upright. *2 BROWN / purple on convertibles.