I think that there's not much value to monitoring movement before 28 weeks, because before turn it can be hard to tell the difference between baby and for example wind. Having said that I'm sure I went in with reduced movement earlier than that with ds2 and was taken seriously.
Using bio oil here. I had lot left over from last time. 2 pregnancies and no stretch marks at all, so either it works or I've been lucky and am not prone to them! My babies were both small and early (5'11 at 39/40 and 5'3 at 35/40) and had reduced fluid, so I didn't get big at all. Actually I think bio oil is nasty stuff, greasy, stains etc, but I'm convinced it's the best thing for the job.