I think they have to notify the opposing team to give them the opportunity to ball the same time.
Nope, notification of the opposing team is just a courtesy unless otherwise provided by league rule.
Commonly Asked Questions – Rule 111e.
111e/1 If a team is granted a pre-bowl or postponement and the opposing team is not notified, are the games forfeited?
No. When bowling unopposed, the opposing team does not have to be notified (or agree to a date) prior to the time of bowling, unless otherwise provided by league rule.
Notification of the opposing team is courtesy and games cannot be forfeited. If the league adopted a rule requiring notification and the opposing team was not notified and filed a written protest, the league board would have the following options:
a. Games stand as bowled.
b. Null and void both teams’ scores and require both teams to re-bowl in direct opposition.
Is a league officer going to be there when they bowl? I believe there is a rule on that when a team is going to pre/post bowl.
Again unless otherwise provided by league rule, a league officer doesn't have to be there.