Please search the forum before starting new topics. Your approval suggestion is already in the ideas category: Multi Level Authorization - #3 by Abeiku.
Your idea for a payment option is questionable, because not all expense claims are reimbursed directly as standalone liabilities. Those where the expense claim payer is an employee or capital account owner are credited directly to Employee clearing account or Capital accounts. See Use expense claims | Manager. Having such a button risks accidental mishandling of expense claims.