GHT Jr just turned 2.....and we leveraged Aeroplan for all our travels during the first 2 years...... Here is what I understand:

Option 1 - Book Aeroplan tickets for adults, and add kiddo for $100+tax or 10,000 miles. In this option:
(1) most airlines reservations will lock your PNR and you cannot select seats in advance
(2) big bird you may be able to request for a bassinet, however it sits on your lap on planes w/o bassinet
(3) most airlines kiddo is limited to baby meal (BBML). I only had 1 exception experience on another *A partner

Option 2 - If you want a seat for kiddo, then its another reward or revenue ticket
(1) everyone gets a seat
(2) everyone gets a meal and you can request for child meal (CHML)
(3) expensive & costly, something I personally would wait for 2+ when it becomes mandatory
(4) some airlines may have issues w infant and J/F pods

Personally, I look at Option 1 as a limited time great deal offer!

Hope this helps.
GHT