I've taken part in at least 6 taiko tournaments over the past 10 or so months so I'll give you my insight based on my previous experience.
The average length of a match depends on multiple things. The number of players involved in a match (which isn't really a factor since this is a 1v1), the win requirement (first to 4,5,6,7 etc.), the average length of each mappool, the average time it takes for players to pick and ban maps. On top of that you got to consider warmups by both players and the possibility of issues that might arise from either players, bancho, refs or streamers as its tends to happen in every round at least once. A general rule of thumb I use is for a match that has one warmup per player + first to 4 win condition. I say around 75 minutes maximum unless a serious issue delays the match. Most matches take between 30-60 minutes but I always assume that it'll be a close game that reaches tiebreaker point. So when planning your match times and days keep in mind that it should take up 75 minutes of your time. For every increase in first to x matches (as they increase it from first to 4 to first to 5) you should add 15 minutes to your expected match time.
It is not a problem what your PP is. In ANY tournament, there is either a rank condition, a pp condition or no conditions. In this tournament the top 150 players in taiko are not allowed to play and you gotta be in Asia+Australia+Russia to play. Other than that they don't care what your pp is. This tourney is expected to have 32-64 players. The only time your PP is a problem is when over 64 players sign up. At that point they will only take the highest 64 players that sign up. This probably won't be an issue so you don't need to worry about this I've been playing in tournaments since I was 6k in rank with around 2.8K pp. once we get more info about the range of skill of the players signing up, we will have a good idea of what difficulty of maps to start with. My guess is that the maps will begin at approximately the 4* level however, just because it's 4* doesn't mean it'll be easy take shiwatse for example from the TWC group stage earlier this year. Honestly you're probably end up being in the top half of the competition. I assure you in this setting you'll fit right in.
The hours are adapted in the sense of scheduling and streaming for the most part, however that being said the scheduling in any tournament ultimately comes down to whoever is playing. Naturally, the tournament staff will create a schedule for all players taking place at the evening time for players but you are free to talk your opponent and reschedule for another day or time.