Hi.
Yes, about anything that can be done with unity can be done with playmaker.
for network i would suggest Photon, but there might be other network solution.
other assets might be useful but it totally depends on your project.
Lan should also be possible.
But if you just started with making games you might want to start by following some tutorial series and build simple games, else you might hit many walls and get stuck and get frustrated and maybe even surrender.