Welcome to Librarium Online!
I am going to buy a second hand army with a few models. I can make from it the folowing 35 points list:
unit: temple flameguard (leader+9)
mercenary solo: eiryss
I will have to use that list becouse that is the only things I have, but I just want to know weather this list stand a chance against anything.
In the cases that I could borrow some models from others, how should I change that list to be better?
The list will hold up fine, but I'd suggest adding some more units to fill out the list as you'll be vastly outnumbered 80% of the time at 35 pts. I'd suggest dropping both devouts and pick up the Temple Flameguards UA. After that you'll want to pick whatever you like most, although a Choir with that many 'jacks won't go amiss. I'd personally suggest getting the Knights Exemplar as they pack a nasty punch and are hard to kill once you start taking casualties.
Other than that I'd suggest getting some games in. Once you get a feel for the game and your play style try proxieing some units/solos to try out different set-ups. Menoth has a lot of possibilities with synergy and tiers, so try out lots of things before you buy new models.
Best of luck!