I don't know what the procedure is if the House Speaker resigns or dies. I presume there is a new election for the position or perhaps one of the deputies takes over. Either way, there is a solution.
MF take the post and if Pita is elected to be PM then the MF House Speaker resigns and MF vote for PTs choice.
A faction of PT led by Adisorn, are insisting PT get the House Speaker's post, even though they know full well Pita has little hope of becoming PM due to the Senate.
Watch out MF, PT will get the two most important posts in spite of coming second.