UPSC

Both the courses can lead you to a successful journey to UPSC performance. If opt for PCM then you can take maths as an optional subject. You should know that if you are strong at maths then you will have an extra edge over other aspirants because in maths you have exact ideal answers which will reduce the risk of losing your marks just because your answer will have a different perception.

If you join any of the courses which have some connection with UPSC like BA, LLB and B.Tech then you will have an extra edge over other UPSC aspirants. Also, if you are dedicated then the course will not matter.

Hello,
CAT is surely easier than UPSC since one needs not to spend more than 6-8 months to prepare for it. In addition, it tests candidates only in three areas: English, maths, and logical reasoning.

Minimum percentage required to be in eligible for UPSC is 40% only. After that, you can be able to get application form valid. Otherwise, you can't be able to apply for this.

Here are some of the best coaching classes, which are best in India for an IAS Exam Coaching:
Lakshya IAS Academy
ANALOG IAS INSTITUTE
Mumbai Institute for IAS civil service examination preparation
A. Shah's IAS
ALS IAS
Time IAS Academy
Paradigm IAS Academy
Narayana Academy.

Yes, you can go for UPSC examinations after UG in hotel management. UPSC says you need to pass your graduation in any stream. So, there's no such preference criteria for different stream of graduates.