How about using «'ej» with the jIH-form of the previous verb?
«juH qach vIghaj» (“I have a house.”)
«'ej vIghaj» (“Me too”)
I don't think that works. Without the {je}, it feels like an object is missing. For example, I would accept the following:
{juH qach vIghaj} "I have a house"
{'ej jem'IH vIghaj} "and I have a castle"
Without the object, {'ej vIghaj} sounds like "and I have it", but what is "it"? It sounds like the speaker is claiming to also own the same building.
«vIraS vIjaH vIneH» (“I want to go to France.”)
«'ej vIneH» (“Me too”)
Whether it's {'ej vIneH} or {vIneH je}, I'd interpret that as the speaker wishing the other person to go to France:
{vIraS vIjaH vIneH} "I want to go to France"
{'ej vIneH} "and I want it" / {vIneH je} "I want it too", i.e., "I also want *you* to go to France".
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De'vID