Thank you for your questions.
#1: Yes, for a table that consists of nothing but words and unmodified numbers, it's UEB all the way.
#2: A table that has one entry that must be in Nemeth Code is not required to have all its rows in Nemeth Code. In the example you provided (where a row heading and an entry both include material that must be in Nemeth Code and there are no column headings) I think I would suggest transcribing the body of the table all in one Nemeth bubble, with the opening Nemeth Code indicator in cell 1 on a line by itself right before the first row and the Nemeth Code terminator in cell 1 on a line by itself after the last row of the table. But I do not believe it would be wrong to enclose the fraction in the row heading in one set of Nemeth Code switch indicators and the fraction in the second column in another set of Nemeth Code switch indicators.
#3: Our Guidance does not require that (x) in "Number of Sheets (x)" be transcribed in Nemeth Code. So, there is no technical material in the column headings of the third example table you shared. You're quite right that the decimals that make up the second column's entries must be in Nemeth Code. So, you should enclose the row headings and table entries in one Nemeth bubble, with the opening Nemeth Code indicator in cell 1 on a line by itself following the column separation lines and the Nemeth Code terminator in cell 1 on a line by itself after the last row of the table.
Thank you for your questions! Please let me know if you have any follow-up concerns.