I don,t think you'll get a response from memorymaps support network, they seem too pre-occupied with everything android/iphone/pc.
But i'll give you my take on your problems, with regards the red direction arrow....this is used to display your general walking direction and the arrow increases/decreases with your current speed... an example would be if walking/mtb fast the arrow extends.... if walking slow the arrow shortens, but i never use this for routes, its just there, i don't really take much interest in it.
For routes i use the two boxes that appear when activating follow route, these will be resizable info boxes that pop up on your map screen, myself personally, i get rid of the one info box by using its close button and just use the blue arrow direction pop-up box, this should give you what your looking for when following a preplanned route.... but be aware you must be moving for this to function.
Not really sure about your second point, are you saying that when the screen locks and you then unlock it the overlay data is missing, its been a while since i used the 2800, i now own the 3500..... but if i remember correctly there was an issue with the POWER DOWN TIME setting, this caused issues for some, i believe support stated to leave this setting as always on and stated it was never meant to be used for the unit, it was meant for the golfing app that can be purchased seperetely.
Now i'm sure i may have missed somthing, if so..... there are others who may just post to correct me.
Samsung nexus s 4.0.3
ice cream sandwich