SPOILERS
I have decided not to kill Paarathox till alot later down the line, but as for companions to be blades, any can be, just take them there, at first i sent Faendal, was good he could still be recruited, but he wasgiven ful blades armour,sheild and sword, just didnt seem right to me, hes an archer, so later on im goin to take people who fit the bill a bit more, warriors with sword and sheild themself, who also seem to fit being a blade, after all there really there to protect me

so Housecalls are good choices.....