You will have to ask them...but I would presume the president of Ukraine who stated publically that he was NOT PRESSURED in anyway would shoot the whole proceedings down!....Why even bother showing up for work when Republicans can't cross examine, they can't call witnesses, they can't subpoena, they aren't privy to vital information, and they only hear information when it is splashed up on news tickers on cable news shows when they see the words "sources say." Republicans might as well show up when Dems say they are ready to open it up.
Schiff won't allow anything opened up because he says Republicans will share information, but someone is still leaking, and they turn out to be leaks that support the Democrats' narrative, they are Orange Man Bad, and no way to cross examine them in real time like all others before have allowed.
The Constitution says the House has power over impeachment, but that does not mean Pelosi, nor Schiff, nor even just the majority.
I''ll bite, what witnesses would the republicans call??