My question involves business law in the state of: Washington

My father formed a partnership between myself and my two siblings, and the Partnership Agreement was to be interpreted under the laws of Missouri. The eldest was set as Managing Partner (MP) but provisions in the Agreement allow the MP to be replaced for cause. The Agreement shows that each Partner has one-third interest, but no distinction is made between ownership and voting interest. The original MP lives in Missouri but the two other Partners live in Washington State. The Partnership has an investment account and checking account at a major bank/brokerage in the name of the Partner, with the MP as designated contact and with a copy of the Partnership Agreement filed as part of the application process.

As a regular Partner, I borrow a sum of money from my interest and am unable to pay it back. Later, the MP ceases to perform her duties and ceases communicating and performing the duties of the MP. The two Partners ask in writing for the MP to answer email, mail and phone calls to deal with business of the Partnership. No replies are received by either Partner, likely because of some perceived discord between the MP and the other Partner. After all, these are siblings. The two Partners follow the procedure contained in the Agreement and notify the MP that she is replaced, with the other Partner as the new MP. The bank acknowledges the change in MP and changes the contact for the account to the new MP with address shown in Washington State.

The original MP objects verbally to the bank/brokerage and then goes incommunicado again. The bank freezes both accounts and informs all partners that all orders to the bank must now be received as identical orders from all three partners in writing or that the Partnership must present a court order instructing the bank whose orders to follow. After several years, the current MP has shown that she has failed to act to break this deadlock and has ceased caring about her fiduciary duty as MP, based on inaction and lack of communication herself. After many attempts by mail, phone and email to have the former MP respond, I am prepared to bring suit against both other Partners and the bank. As I reside in Washington State as does the current MP (and as the Partnership is listed here, as shown in the bank's records), I know that I could bring suit against the Partnership and the current MP in Superior Court in Washington State.

Q1: Is the stipulation in the original Agreement regarding the laws of Missouri an impediment to a suit brought against the current MP, the former MP and the bank?
Q2: As my money is tied up in the bank, I intend to pursue this pro se. I believe I can craft an initial pleading but would like to locate an example or two of Superior Court pleadings. I have reviewed the Superior Court guide to pro se and understand the format. Where could I obtain examples?
Q3: I can sue for my share of the accounts easily, but how difficult would it be to add damages due to business losses and emotional damages?
Q4: Any other suggestions?