Yes I'm pretty sure this should work albeit potentially a rather costly operation for both the light client and the witness involved. 👍

I notice that we still have this check in place:

        // Validate the number of witnesses.
	if len(c.witnesses) < 1 && c.verificationMode == skipping {
		return nil, errNoWitnesses{}
	}

Do we want to extend this to sequential light clients requiring them to also have witnesses or not? Personally I'm leaning towards leaving it as is and not requiring sequential light clients to have witnesses because this is not a default setting and if people are changing the defaults then I'll assume they know what they are doing and also this attack is much more difficult than with skipping.