I painted miniatures with regular acrylic paints exclusively for many years, and still do technically although I've mostly switched to a matt-finish brand (Jo Sonjas).
These acrylics are probably okay to use, but they're likely to have a few issues you might find a little trying.
The first is of course you need to thin them quite a bit to use them; you can get used to this but it is a big chore, especially if you haven't developed a reliable method for doing this when you're mixing (I mostly mix on a ceramic tile using a painting knife, then transfer the paint to my stay-wet palette).
Next issue with artists' acrylics is that they have a wide natural variation in covering power from colour to colour based on the natural transparency of each pigment. Some colours will be very transparent, others quite opaque.
I don't know what these ones are like specifically but I can make an educated guess based on their marketing blurb and them being sold at a unit price - they're higher-end student acrylics or studio acrylics. Despite what is claimed they may be very similar in qualities to W&N's Galeria or Daler-Rowney's System 3 ranges. This means they are probably not as highly pigmented generally as they could be so coverage could be less than you'd like overall, even with colours like Titanium White and Yellow Oxide which would be naturally opaque.
Another thing is of course you'll have to mix a lot more of the colours you'll need, compared to using a hobby paint like VMC for example.
Last issue is their finish. They may dry to a consistent finish, in which case it's probably going to be roughly satin, so you'll have to fight that on a constant basis. Alternatively they may display a range of finish, from quite matt all the way to pretty glossy, depending on the colour. In which case you'll also have to fight this on a constant basis
The watercolours are probably fine to use for things like weathering and other very subtle additional touches on top of the normal paints, if you're happy with them being water-soluble when dry so lifting of previous coats will be a consistent problem if you want to apply more than one layer.
Einion