Great post,but:
Problem 1.
<< MaTex`
(*$Failed*)
Problem 2:
Integrate[Floor[Log[b, Floor[Ceiling[x]/x]]], {x, 0, Infinity}, Assumptions -> b > 1]
(*Integrate[Floor[Log[Floor[Ceiling[x]/x]]/Log[b]], {x, 0, \[Infinity]},
Assumptions -> b > 0]*)(*Give me input*)
I executed this code on Mathematica 12.2.0.