I used hot water and a clean washcloth to get the residual icing out and then a hot Oxyclean (or PBW) soak. Good rinse and you are ready to go with sanitizing.
I harvested slurry from a previous batch and used Mr. Malty to pitch appropriate amounts into my 2 gallon batches. You could do the same thing with a large starter.
I did 7 x 2gallon batches of single hop IPAs. Named them after the 7 Dwarfs. Grain bill was 85% 2 Row, 6% Munich, 5% Crystal 15L, 4% Crystal 45L.
No reason why SMaSH wouldn't work just as well. For me, since I had 14 gallons of IPAs to drink I wanted to make sure they had enough malt complexity...
Grain absorption is usually around 0.1 gallons (a little less if you BIAB and squeeze, a little more if you do a traditional all-grain). So you'll lose 2.3 gallons to absorption, leaving you with only 4.8 gallons of wort. You'll also need to account for boil-off, which is contingent on your...
Can't speak to the blanket question, but I do the same thing for my partial mashes or stove-top all grain. YMMV but I've found I need to heat my sparge water to almost 190F in order to sparge at 165F because the grain bag cools as the sparge is heating.
And then I found out there were only 3 entries. I'm significantly less proud now than when I found out I won :(
LHBS put on a stout competition and my beer won with a score of 35. Yes I know, a good score, but I was hoping for a bit more competition to see how my beer stacked up...Oh well...
Well your grain bill is consistent with a partial mash, but your technique is more in line with extract with steeping grains. The key to "mashing" is proper temps (usually 148-158) and proper water-to-grain ratios (1-1.5qts/lb). I'd look into this...
Do you have enough time to brew a 5G batch of small (low OG) beer? That's what I'd do and use the yeast cake. Something low gravity, low hopped would be best.
Technically Munich has enough diastatic power to convert itself, although adding a pound or two of base will help you get full conversion. Other grains vary.
*My* rule is as much base malt as I can fit, which for my 4 gallon kettle is around 8lbs total grain weight. This helps with cost...
If you don't have a large enough 2nd pot you can do what I do. Mash in kettle using grain bag. Drain (I squeeze) bag of all first runnings. Transfer your first runnings to a food-grade bucket. Heat sparge water in kettle, once you hit your temps put your grain back in.
You could try a lambic. Pretty sure they require old hops. But I think there is a particular way to age hops for a lambic. I've never brewed one but it could be interesting.