Sometimes it's not about pulling the goggles tighter. In fact, it usually isn't.
It is important to get a pair that fits properly, but that usually isn't very difficult. A tiny droplet after 15 minutes doesn't really count as a leak. I would imagine that you are having similar issues to me from when I started. I've got a couple of crow's feet, and try too hard. Therefore my face will show the effort and tense up. The more I've swum, the more relaxed I've become and fewer leaks occur.
My first goggles were a foam edged racing pair, designed to be scragged really tightly, so that the racer could dive in and pound the water to froth. The chlorine and age made the glue give up.
My current pair are Zoggs, (Phantom) nothing fancy. Silicone edge seal is the most popular for being a good seal, but they do the job really well.
Cramps. Again, it's primarily about not relaxing when runners turn to swimming. Obviously there are a load of contributory factors. Hydration (yup, even in the pool), salt balance, cold water, (well, it's cold if you're not thrashing repetition lengths), swimming for longer than before, and holding tension in your muscle for extended periods of time.
So. Take a 500ml of weak juice. Push off the wall with your feet, especially if you are feeling the onset of cramp in the foot. Relax. If you need to swim more slowly, then so be it. Build the endurance then go back to increasing the stroke rate when the stroke is better.
I'm not the expert, I'm just a beginner in the thick of it.