Yes, it would most likely cause some inflation of consumer goods, since poor people spend more of their money on consumer goods than rich people (so when you transfer wealth from the rich to the poor, consumer goods will become more expensive)
This increase in consumer good prices, however, will also cause more resources to go into producing goods for poor people (who suddenly aren't so poor anymore). Depending on the limiting factors for these consumer goods, this will most likely cause prices to stabilize at a reasonable place.
No.
You are ignoring the fact that this is in effect a redistribution of wealth.
The answer is no.
> I fail to see how there won't be some kind of inflationary situation amongst the lower class
Ignoring any potentially counteracting monetary policy intervention, there absolutely will be some price inflation for goods disproportionately in demand at the low end of the economic distribution. Reasonably, you expect both market clearing price and market clearing quantity of such goods to increase with a transfer of income to that group (and UBI funded by tax is a transfer, in effect). In short, nominal net beneficiaries will get more stuff, but by somewhat less than prices before the UBI would suggest.
Essentially, production will shift from things demanded by the net contributors to things demanded by the net beneficiaries.
My simple question I always pose is this: "If everyone has $X dollars, then wouldn't $X become worthless?"
I fail to see how there won't be some kind of inflationary situation amongst the lower class, especially in the form of rents over the course of a year as leases reset. I also refuse to accept any argument that involves the majority of landlords "doing the right thing".
Thanks for posting the Law of Rent.