Apologies for the delay getting back to you Lulu05.
Based on your reply #3 it really is a matter of your personal preference as only you can decide if you would rather have less RAM and a smaller screen but the benefit of having the 2 in 1 option, if you do not intend doing any serious video editing you will get by with 4GB of RAM but 8GB of RAM would be better + you would get the best out of your 64-bit OS with 8GB of RAM.
What is RAM actually for?
RAM has more than one use, the main one is temporarily storing data as opposed to the data having to be written to the hard drive and the second one in the case of computers that rely on internal graphics the RAM supports the integrated graphics solution, basically having more RAM allows a user to have more programs running, internet tabs open and provides better video support.
The tablet/PC combo is appealing just for not having to have the laptop always on my lap or on my sofa overheating
Notebooks should never be used on anything other than a flat, firm and even surface, this allows the air to flow around the computer, allows the exhaust vents to expel the hot air from inside of the chassis and avoids the internal cooling fan sucking in dust and other debris such as pet hairs that can clog up the internal cooling fan and result in overheating.