Here's [1] a study from the Pew Research Center stating that 51% of Republicans believe the poor are poor due to "Lack of effort on his or her part" rather than "Circumstances beyond his or her control" (32%).
And here's some prominent Republicans saying similar things over the last couple years.
Typically, the point is framed as a "lack of work and effort" or a "problem with culture" rather than explicitly saying laziness is the cause of poverty. I would say the unifying thread here is that Republicans believe the poor are poor of their own volition and choices, whether that's laziness, poor decisions, or a "poor culture" (what does that even mean?).
So yes. I would say that in general, many Republicans have called the poor lazy, and while it isn't the specific verbiage they like to use in public, it is the opinion of their constituents.
Not the ones I read. Could you cite some mainstream examples?