Z24 stall issue and interior & headlight flicker when door is open or foot on break

My '98 Z24 2.4L v6 coupe cavalier has some issues.
1) My car idles around 500rpm and never higher unless my foot is on the gas. I've noticed when going through drive-thru's my rpm's will dip while waiting with my foot on the brake. I have also heard what I assume to be the fan kick on once it dips. When the rpm's dip its never lower than 200 rpm and then I feel a little shake or sputter like when a car is about to stall but it doesn't stall, just the fan kicks on.

2) Stalling out once in a very while (when on hills) and never gives off any signal its stalling or stalled other than my power steering shuts off or I just happen to look down and notice. It doesn't shake, rattle, or backfire, it just shuts off like it does with the key.
When driving for about 45-90 min and after I got to where I was going I turned my car off, parked it for a couple hours (1-3 hours on flat/ level ground/at least half tank of gas). When I start my car & I'm coasting down hill or braking down a hill that is within feet of the resting point, it will stall out before I reach the bottom of the hill. It starts up and drives without any issues afterward. The outside temp has been around 85°F(day)/65°-75°F(night), no rain within 24 hrs or since last drive when it has stalled. I didn't really let the car warm up for more than a min since it was fairly warm out. Alternator has been replace within a year or 2, battery isn't more than a couple years old, on time with oil changes and maintenance.

3) Dome light, Dashboard, Head lights, Tail/Brake/Reverse lights Flicker.
If I have my lights on at night I have noticed the exterior lights will flicker when in park with my foot off the petals. If I come to a stop while driving or parking with my foot on the brake its even more noticeable than before. When I park in the garage I can see ALL my exterior lights flickering head/tail/reverse/trunk brake light and its not faint by any means.
The dome light flickers the most drastic when the exterior lights are on and a door is open. If the exterior lights are off it still flickers but not as noticeable. I have turned everything off that could be drawing power (heater/AC/fan/radio) and nothing has reduced or helped.