Marcus shows up beside the tent on the right side at 9 or 10 am, near the beginning of the game when you have to get water, you will have to follow the boys and peak in order to start the stealthiness trait,as it gives you the first 10 friendship points, and later when you have the letter from sophie, showing marcus will give you the other 10 friendship points. Warning talking to him again right after you show him the letter will start the invisibility quest and take 2 hours off your time for other things.
after this he will show up in the middle of the trees just above heather's home, when the secret pond quest starts he will disappear for 2 days, he goes to try and find a way not to get caught peeping. He returns and asks you to find magic mushrooms in the forest. ( you can buy magic mushrooms from brooke if you have enough friend points ).
As for the tavern bug ( friend points not initiating when evelyn talked to or gift given.. unknown. As well the tavern job board not initiating is an other bug. )
If you are following the walkthrough note it is not done properly.. certain things are not explained, like seeing the vincent/roxie sex scene ( 5th day before 5:30 am look for stars on the left side of house .. save before you start, if you don't see them reload until they show up... as well it can be done on the 4th day ( it did for me anyways ))
the massage quest from darius .. must have below 50 coins in inventory.. choose mia or heather to pimp out to him. talk to who which you choose and go back at 17:00 pm to start it. Supposedly after Mia visits Darius, the Mia relationship line will start, when she is taking care of your father you should find her in a chair next to him one night ( walkthrough says day 3.. which is dumb since she doesn't start taking care of him until day 8 )... ( note the mia massage mission is bugged, mia still hangs around by darious and says the medicine doesn't work, even if you have helped her and said not to do the massage. )
As well i have yet to actually see mia in the chair in your house, supposedly able to take advantage of that situation, haven't been able to start that part even with the walkthrough.
( yeah the game has lots of bugs that should have been fixed 2 years ago )