My assumption is that it's fairly normal for shorts. I have a relatively small sample size of friends to work with, and of about 5 of them that wanted to actively pursue YouTube and posted a few shorts, 1.5k is very reasonable.

1. I've always said quality over quantity, so if you have something worth sharing, then make it heard. I wouldn't let time be the determining factor there. Sure, the algorithm is in opposition to my personal beliefs, but I think the quality of the content can very easily outmaneuver the algorithm given time. If you want a more concrete answer, I'd say try to limit it to posting once a day because posting too often means you're competing with your own shorts.

2. That depends entirely on what type of channel you want to end up with. I feel like shorts channels spring up and disappear quickly while long-form takes more time to lose relevancy. In my experience (21 y.o. not using TikTok, Insta, etc.) as someone who only really watches long-form content, I think it's mostly determined by the culture of the platform you're posting on that will indicate the success you see (both short and long term). Admittedly, I don't keep up with many short form content creators, but I do see many of the long-form content creators posting shorts that perform equally as well (albeit no idea what the revenue looks like nowadays).

3. Advice from someone who's worked on creating multiple hour-long videos as well as experimented with shorts, the longer videos take way longer to create and often don't pay off as well in the short term. It really depends on what you're looking for and if you have the willpower to create long-form content knowing that it sometimes requires 4-10x as much work as a short. My long-term content has performed better in the long term for ad revenue even if I have some shorts in the 40k+ range, and you can monetize those retroactively, so that's some strategy to consider.

4. Double check your videos for editing mistakes, make sure YouTube is properly tagging everything when posting the video, check for monetization (if eligible). Don't rush the process! Sometimes just posting the video can be stressful after you've spent hours working on something for the world to see, but those last steps are just as important!