Republicans and Democrats in competitive districts can not vote for impeachment in the House unless there is a credible offense that Republican and Independent voters would agree is credible.
To date there is nothing like that, so Schiff is basically on a fishing expedition trying to find something like that.
I doubt we will ever have an actual impeachment vote unless the Democrats decide it is OK to vote and fail to reach a majority.
The Democrats only have a 17 seat margin above a bare majority.
The Democrats picked up 40 Republican seats in 2018. How many of these will be willing to vote to impeach, assuming they want to be reelected?
To get a successful Yes vote the Democrats would have to create huge electability problems for many of their members.