Silicon's conditions would make it difficult. It has far less inorganic precursor molecules to work from. It might work under cryogenic conditions, but that has a bunch of other problems.

The titanium one is new to me, and potentially interesting. My concern would be an abiogenic pathway. It might be able to form interesting molecules for life, but if they don't appear naturally, then getting life started gets massively more difficult.

There's also a hell of a lot of options with carbon based life. Earth life is VERY locked into a few variants with our base biochemistry. E.g. there's no reason for particular RNA sequences to match particular Protein peptides. Yet it's basically a universal thing. Even chirality is fixed, for no particular reason other than mixing causes issues.

I could potentially see a dual based life system working, effectively a more advanced version of how some creatures use metals to make shells etc, or how horns and hair grow. It could also provide a viable (though extremely convoluted) bootstrap process for titanium life, or something more exotic. Forcing life to change its core functionality however is apparently quite difficult, since no life on earth seems to have done so and survived to be detected. Rocky, in Project Hail Mary, would fall into this group (a carbon life core basically piloting a stone and metal mech).