@twobob: If you keep them completely separate, and don't try to mix and match in the same process, like you were doing, it's safe. It's actually what's a multilib system is doing
It's not necessarily always easy to manage, which is why we've nearly all been staying away from multilib systems/TC
. Granted, the only experience I have with this is a bit rusty, with Gentoo's native x86_64/x86 multilib profiles.