I second the feeding several small meals as toy dogs (especially puppies) often have troubles with keeping their blood sugar levels up.

As for the question on bathing you can definitely bathe him now if you want/need to. Use dog/puppy shampoo and conditioner and make sure to rinse thoroughly and then dry him right after so he doesn't get a chill. Best to start him young so he gets used to it as he is of a mix that will need regular grooming, whether you do it yourself or take him to a groomer. If you do end up taking him to a groomer then your groomer will thank you for starting him young.

Congratulations, good luck and have fun!