This is close but not entirely accurate...
R262s are intended for the for Lex CBTC and (with the caveat that the and interline frequently); the and will get the rebuilt R142/As for 7th Av CBTC, whenever that happens and the seems destined for an R142/R262 mix. These were mentioned in the documents for all three projects (R262s, R142/A rebuilt and Lex CBTC) and I again stress that things are subject to change.