Houston METRO Commute: Grand Parkway P&R to POST Houston

I am planning to commute downtown via the METRO Park & Ride Route 222 (Grand Parkway P&R Express) and need to arrive near POST Houston between 7:30 AM and 7:45 AM, and I need some help.

1. What is a realistic, total travel time from the Katy area to downtown during peak office hours?
2. How reliable is the Route 222 service in hitting its scheduled arrival times downtown? Are major, frequent delays common once the bus enters the city approaching downtown?
3. What is the best time to get on the bus at the Grand Parkway P&R to get to work on time?
4. Which drop-off location is the most convenient for walking to the POST Houston building? Is Preston St @ Bagby St the best option, or is there a stop that offers a shorter/safer walk in the early morning?
5. What is the general feeling of safety and walkability around the final downtown stop and the POST Houston area?
6. Which mobile app do you find most accurate for real-time tracking, schedules, and alerts for this specific P&R route (e.g., METRO's RideMETRO app, Google Maps, Apple Maps)?

I appreciate any clarifications or advice on this.