Probably a good opportunity to try washing yeast but it's such a small batch that you'd do just as well to pitch some new yeast. Definitely give the yeast washing a shot, it's a useful skill, just don't hesitate to throw it out if you think it may have picked up some bugs during the process.
1. You can over pitch which may result in underattenuation and some off flavours in the final product as the yeast doesn't have the opportunity to 'mature' as the must is fermenting. It's a good idea to use the Mr. Malty yeast pitching rate calculator to get an idea of how much to pitch.
2. I usually leave my ciders in primary for 3 weeks before transferring to secondary but a month should be fine if it's more convenient for you. I've found that leaving the cider in primary for too long (IMHO 5-6 weeks) hasn't had a huge impact on the flavour of the final product but certainly affects the nose. John Palmer talks about the effects that a long primary fermentation has on beers in "How to Brew" that's worth a read.
3. Pasteurizing after carbonation is a great way to preserve some of the sweetness and apple flavour that can sometimes be lost on bottle carbed ciders. I like dry ciders but simply bottle carbing without pasteurization using nottingham is a tad too dry for me. I use kegs now but bottle pasteurizing worked like a charm the time I tried it.
Primary: Edwort's Apfelwein
Primary: Brewingcentres Pale Ale
Primary: Brewcraft - Cheap 'n' Shiddy Bavarian Wheat
Kegged: Brewcraft - Cheap 'n' Shiddy Bavarian Wheat
Kegged: Brewcraft - Enhanced Dutch Lager
On Tap: Brewcraft - Irish Stout