Just put Single Sky feed in my room and parents room

Iv got a Humax Freesat HD box which im happy with but in my parents room theres a very old Panasonic box must be atleast 10 years old without a card...

Can I upgrade this to a Sky+ box without etc sub?

Do all Sky+ boxes need two feeds? Whats my options? I have got two spare Sky+ boxes one with card and one without can these be used?

Also channel 5 seems to be missing and perhaps some other channels I dont know

Sky+ requres subscription. You can use sky+ receivers with a single feed and no card, just for the free-to-air channels. Channel 5 will need to be added to the 'other channels' list unless you have a valid card (subscription or FTV).
Hope that helps.