I used BAL grout when I did my en-suite a couple of years back - mainly
because I needed a coloured grout. But this stuff happens to have Microban
They do a white/flexible version too
I've noticed that whilst there is a bit of gunge about elsewhere, the BAL
grout looks as good as it did the day it went on (it was the champagne
colour which is still light enough to show any mould up clearly if any had
Then again, if you use a shower cleaning agent regularly (they are typically
a mild bleach solution) you should be able to keep the mould at bay before
it takes hold anyway. A nail brush is handy for scrubbing the stuff well in.
BTW, the BAL grout is still good in spite of the fact I've not actually used
such cleaners on it yet.
On the tile-to-bath, any good silicone should do the job, but check whether
its power-shower compatible (if you have one). Tip - make sure there is no
flexing of the bath when you stand in it (e.g. poor supports etc. - if so
fix the problems or you're wasting your time as silicone will only flex so
far) and when you're ready to seal, fill the bath right up with water so
there is plenty of weight in it and leave it like that as long as you can
whilst the silicone cures.
Your extractor will be fine for ventilation, but ultimately, mould will take
hold wherever water stands or is trapped and that tends to be along bath
sealing, shower trays, behind soap dishes on walls etc. - and spreads from
there. Nothing unusual I'm afraid.