there is a high risk that one or more would slip up (talk to someone, or make some fatal mistake)

Potentially, but also MKULTRA. I'm sure they have body doubles that are mindfucked beyond hope or any possible redemption, and will do exactly what they're told, and even if a brainwashed broken body double did try to speak the truth, you know well the MSM would suppress any info on that. The body doubles make plenty of mistakes. It's why us anons are constantly pointing out the possibility of body doubles and using irregular audio and visual cues to help us. The Biden earlobes being just one example. Also, you know hyper-realistic masks are a thing. Not saying these body doubles are just walking around wearing hyper-realistic masks, but my point is that it's very easy, especially when you're the DS, to make fake things look real. It is after all what they specialise in. Lies, illusions.

With regards to Biden specifically I feel like he has only one body double, and he seems to be totally loyal (controlled? brainwashed, broken?) to the DS. I believe the real Biden is dead. This is in contrast to Hildebeest and others, who seem to use multiple body doubles. Biden seems to just use one. Well, his handlers I mean, but that's obvious...

I won't pretend to know enough about clones to really comment on it. I've only read a bit about it. You should check out Donald Marshall's story if you want to hear more about clones. It is absolutely wild but it seems genuine. I've yet to make up my mind about it. But I will say, knowing the capacity of the globalists, the level of cutting edge technology they are willing to manipulate for their own goals, it is absolutely not beyond the realm of possibility, IMO, for them to have cloning technology. Whether or not they actually do is a different debate, but I at the least think it's plausible and possible. The specifics though, I have no idea.