Quote from: LoyceV on Today at 09:54:51 AM

I assume this setup would use offline signing, in which case different seeds don't increase security.

Still a central point of failure, where one seed gives you more control than it should and the compromise of a single seed equals to a compromise of 3 entities and only requiring the participation of one more. Nevertheless, that is not the point as security of seeds isn't the central discussion here.

Quote from: LoyceV on Today at 09:54:51 AM

You don't need to use different derivation paths, you can simply use different addresses/keys from within one Electrum wallet for A1, A2 and A3.

That is only if you want to use a single Multisig address without an easy way of avoiding address re-use. So yes, it can work in that case.

Generally, if you want to create a multisig system with HD seeds, then you should use multiple seeds instead of different derivation paths.