Oo the famous eightblack arrives in our forum...

Yes, should be 75K in Y, 125K in J. You can search for award space on Aeroplan.com without having to register for an account. In principle, if it's on United (and/or ANA), Aeroplan will see it.

Cost to buy miles is 3 cents per mile (plus tax). Note buying Amex MR is cheaper (at least in Canada). You can buy up to half of the cost of an award, so if you have 155, you should have enough to buy both.

Aeroplan has YQs, so travel on American carriers if you'd like to avoid it. For reference, I just checked and the HNL-NRT YQ is 196 on NH. There is no YQ (yet) on SQ.

Hope that's helpful.