I think you're over complicating it. He wanted Shirley to go in the kitchen because 1 she shot him and sharron knows about him and her before the wedding so they are not going to want to hang out with her now are they.
As for not getting her out instantly when she went into the lounge, well that was more Sharron wanted Linda round/Phil wasnt involved in it. Had phil been i volved he probably would have, but he isnt so he had no reason to get involved until sharron/Elaine told him to get her out.