1 - NHL Draft. Nothing changes. Scouts would simply have less information on players not playing this season.
2 - OHL draft. I assume some sort of lottery. Same situation with scouting.
3 - Financial. The impacts will be huge. The OHL will require a significant return to play marketting plan. They'll need to recapture a fanbase. They will struggle with both perception of safety as well as motivation. I think many parents will still be a little apprehensive about stadium style activities next winter until they truely feel safe. You'll definitely see a significant reduction in attendance.
4 - Structure. I'd seriously consider cost cutting measures as much as possible. I know the goal would be a return to normal but I am not sure it would be viable. I think we will see a significant delay in the start of the season. Probably a good 4-6 weeks.
There are certainly hurdles that are still on the horizon that is for sure.
As to your 3rd and 4th points, The financial impacts will definite challange, make no mistake the risks and decisions involved will be massive for teams. But lets look at this in a way that is very open-ended here.
The OHL draft becoming a lottery wouldn't be the worst thing for the league in a realistic perspective it would add some interesting spins on the current system teams who used to be guaranteed top picks wouldn't have those locks in the draft and would make draft pick trades much more strategic for teams trying to rebuild.
As for the financial side of the OHL there really wouldn't have to be much change to what is done now yes there will have to be different ways that teams handle fans experiences and players safety but looking from a optimistic view on this teams have an abundance of time to work out protocols and plans for everyone's safety.
These issues can be done on priority basis, for example fans entering and exiting the buildings the QMJHL had already solved that issue early on when their limited return started in where we saw Q teams stagger fans into buildings via specific entrances the OHL could adapt a similar type protocol unique to each teams building for example the Bayshore in Owen Sound has very limited entrances and because of this issue the team could stagger the fans in specific entrances at certain times and on certain days for weekday games fans who sit in the furthest sections from the buildings entrances/exits would be asked to arrive between a time window so say for a 7 pm start time the earliest the doors would open would be 5:30 giving fans from 5:30 to say 6 to arrive at the building and those who are seated closer to those entrances and exits between 6 and 6:30 of course this idea would be solely based on day and game times as well as not every game and team would play at the same times on the same days.
As for game-day amenities teams could adapt to some of what they have in place now for shopping. Fans who would be interested in making purchases could either call or place online orders prior to game day to be picked up, as for concession stands there are teams like the Ottawa 67's who use seat services for specific sections could be used for those STH early bird ticket holders which would eliminate the congestion at concession stands in buildings.
Teams will really just have to plan alternative ways and get creative is all, and this is something that the OHL will have to consider moving forward. Maybe the OHL decides to have a season where the increase the number of games from 68 to close to what the NHL has like an 80 game schedule for the regular season the problem is with the increase of games means that players have more chances of getting injured is the real issue.
Until we see where everything shakes out though we really can only speculate on when the league starts back up on what and how the league will handle next season and beyond.
Lots to consider and for the league to discuss before things get going again...