I would hold off a couple more weeks. WE can still get a real cold snap in February. If the vine is more than 3 years old, I'd prune it to two canes, each of them 12 buds long, and remove the rest of the wood, but wait a bit. Here is a link that might be useful: Google Images

Those mandevillas are glorious! I have never had any luck propagating them, but mine always seem to come back in the late spring. Just about the time I have given up on them, they start sprouting. Last year, I discovered they make tubers kind of like sweet potatoes. i tossed one in my compost pile and it started growing. At the end of the season, rather than trying to keep them going, take up the tubers and let them go dormant. then replant in spring. I have kept one for a long time this way and they are supposed to be annuals here. Those pictures are gorgeous. It's a shame you can't send cuttings internationally. Linda 441 for mother's day, my boys bought me a clerodendrum thomsonae red delectum ( red bleeding heart) and it looks wonderful in a hanging basket. Another favorite is ivy geraniums. They bloom constantly and withstand the heat better than the zonal geraniums.

"The red one got kinda rotten two days later. I cut into it and found no evidence of bugs." You're not necessarily going to find the caterpillar still there in the hole it has made. What makes me think 'worms' is the appearance of the spots in both the first and third pictures of fruit. They look like holes to me instead of cankers/spots, the same holes I'll occasionally get in the spring from smaller caterpillars. And, you had mentioned earlier that leaves were being eaten, which they will also do. "What should I do to fix the problems that you've mentioned?" As far as the splitting goes, try watering a bit less as you've got several fruit reaching mature size. I know, this is sometimes easier said than done in containers. If you were to mulch with some straw, that would help. Another thing you can do is start picking fruit when it starts to change color (breaker stage), but before it cracks. Then you can set it in one of your cabinets for a couple of days to ripen (*not* in a sunny window as some people will advise). Oh, and pick first, then water. As far as the caterpillars go, you can use Dipel dust (Bt) as a preventative. Sevin (which you've mentioned before) also works, but I feel more comfortable using the Bt. If you think that there's still the possibility that your plants have some sort of bacterial spot/canker, I'd recommend that you go the Tomato Problem Solver site and study the pictures for both fruit and foliage.

Do you guys have any pics of your vines? I just started some Cypress from seeds, they're 3 inches tall now, and inside to survive the Colorado winter coming up. Normally I'd start them outdoors in spring of course but I was just too anxious to see what they look like, hence the indoor strategy for the winter...