I've only been an aikidoka for 6 months but I will share my limited experience combining weight training and aikido.
For a frame of reference, I don't consider myself a body builder because I'm an ectomorph at 6'3 and 235 lbs., but I do lift regularly. I usually lift 3 days per week, 2 exercises per body part, 4-5 sets per exercise, 6-12 reps per set, to failure. I usually do a pyramid set for the first exercise and a drop set for the second
One "watch out" in my opinion - you're combining resistance training and non-resistance training. On the plus side, having a nice insulating layer of muscle around your bones and joints is great for ukemi, and I've found that the breath control from Aikido greatly enhances my weightlifting. (I've been thinking about application of the "unbendable arm" principle for weight lifting but haven't experimented with it yet
). The drawback for me is I find I sometimes have to make a conscious effort to mentally switch gears from a resistance mindset in the weight room to a non-resistance mindset as an ukemi, which makes me wonder if switching back and forth is delaying my progress towards non-resistance becoming a natural reaction. You’ll have to explore that for yourself, and I’d be interested in hearing feedback from you and everyone else on this topic.
Another "watch out" that you're quite familiar with - DOMS, or "delayed onset muscle soreness." I’ve advanced beyond the “squat till you puke” mentality I had when I was younger, but I still have a tendency to measure the success of a workout by how sore I am 1-2 days later. Unfortunately, putting a muscle group out of commission can make Aikido painful and potentially dangerous. I’ve found I have to schedule my workouts very carefully around my Aikido schedule to make sure I’m functional for each class. I've unfortunately had to scale back my weigh training some to better accomodate my Aikido, but I'm finding that Aikido is becoming more of a priority over time.
Another “watch out” that you’ve already mentioned – sometimes I can get by with poor technique because I can substitute strength for technique and still complete a throw or a pin. Unfortunately, that’s not teaching me anything. Two solutions (of many) are to train with somebody larger and weapons training. One of my fellow students is 6’6 and 275, and the amount of strength I would have to use to “muscle” him around the mat is so blatantly obvious that I can’t get away with it, which is good. Also, while we don’t do much weapons training at my current dojo, at least not at the beginner levels, at my previous dojo the instructor would have us use a jo specifically to prevent us from substituting strength for technique. Similar to practicing with a larger partner, the amount of strength needed to “muscle” someone around with a jo is blatantly obvious (or impossible) and allows self-or-instructor initiated correction.
My two cents, with a huge caveat that I’m an inexperienced aikidoka.