Former Manchester City forward Miller joins the struggling Glovers on an initial one-month deal having found his chances restricted at The City Ground.
England Under-20 midfielder Lundstram ended last season as a key part of Doncaster's League One title-winning team and will stay with Yeovil for a month.
"They are more than happy for us to take John on loan and we are delighted to welcome him here to Huish Park."
Johnson had been keen to add to his side's attacking options with last season's top scorer Paddy Madden on the transfer list and his current squad having managed just 10 goals in 16 league games since promotion to the Champions.
And his new signings are both available for Saturday's trip to Watford.