Note that as a beginner brewer (I guess I have graduated from that now, but just barely) I too had the same questions, and specifically regarding blow off tubes I figured EVERYONE must use them and I would have to as well.
I mean, I see it on almost every post, there's literally NO WAY I can contain fermentation of 6 gallons of wort in my 6 gallon bucket, right? Yeah no it's fine, I've never used one and only once has my krausen (gunky yeast byproduct head in fermenter) reached the lid of my bucket.
Heck for that matter I've never used an air lock on my beer and this is what, batch 14 or something? Just lid loosely on bucket, bam....no issues.
Yeast starter are only required for liquid yeast, if you're in the dry yeast camp which is where probably 99% of all newer brewers sit (and where I still sit) then you're fine, 1 pack will be fine in almost all situations, for almost all types of beer (exceptions may be very low temperature lagering, you may need two packs, or when fermenting over 8 gallons in a single vessel).