Connective Tissue Injury Prevention for Beginners

Hi, I'm here with a couple questions about appropriate training plans for beginners. I've been climbing since April, and I started Anderson & Anderson's Rock Prodigy program in July. I recently hyperextended the third joint on my middle finger during the hangboard phase (strength phase) of the program (the injury happened while I was climbing a route for fun, not training on the hangboard).

According to Anderson & Anderson, their training program is suitable for beginners. But, after I got injured, I read lots of comments on here about how hangboard workouts are dangerous for beginners because our tendons and other connective tissues are not strong enough to handle this much stress yet. I'm confused about why I'm getting these conflicting messages from people on here and the Anderson brothers. Here are some of the questions I have (although I'd appreciate any and all advice about training at this early stage):

1. Have I incorrectly come to the conclusion that Anderson & Anderson's training program is suitable for beginners? What should I change about my training program from this point on? Once I've recovered from this injury, I only have 2 more hangboard workouts, and I'm supposed to start campusing after that. Should I stick to this plan?
2. What kinds of workouts should I focus on to develop my tendon/ligament strength? I thought that low intensity hangboard workouts would be good for this, but my injury implies that this isn't the case. Are there certain kinds of grips I should avoid training on the hangboard as a beginner because my tendons and ligaments are weak? I've heard that crimps are bad for beginners, but can I still train them if I make sure to take off lots of weight via a pulley system?
3. Is there a limit on the length of a healthy ARC set? Anderson & Anderson make it sound like 3 30 min sets are equivalent to 1 90 min set, but when I've told other climbers at my gym that I've been doing 60-90 min sets, they've told me that this is bad for my connective tissues. I'm a little confused about this because I've read lots of posts about how climbing a lot is the only way to strengthen these tissues
4. How should I handle the aftermath of my injury? I've taken 2 weeks off from climbing to let my finger heal (I've still been doing non-climbing stuff like dips, push ups, pull ups, deadlifts, lunges, calf raises, squats, core exercises, and a little bit of running). I tried climbing again yesterday, but I'm getting pain along the sides of my joint after a couple of climbs. I'm assuming that means I'm not ready to start climbing again. How long would you recommend waiting to climb, and how should I judge whether I'm ready to climb again? (i.e., is some pain ok? is it ok to climb until I feel pain and then stop?)

Edit: I'm going to give my finger another week of rest before I seek professional medical advice. I'll be following the other recommendations you guys have given me until then. Thanks for all your help!