my family did this when i was very small. our family deities are now sri sri radha vrndavana-nata bara and i inherit them when my mata leaves her body. of course you should take them. it seems like they have found you instead of you finding them. deities will definitely choose you or reject you.
and as for this business of "qualified", really! what is that all about? i do not believe that you need to be a brahmana to care for deities. it really is about the prema bhakti and your personal relationship with them. I may not be a "qualified" brahmana to care for radha vrndavana nata bara but i refuse to pass them on to someone else or to a temple (as was once suggested, "they are should not be hidden away in someone's private home, they should be in a temple"). they have been part of my family for over 20 years now and i have a very strong bond with them that in so that i have been worshipping them since i was a 4 year old child. sometimes i get really irritated with people who are supposedly "qualified". govardhana puja my deities were on govardhana hill at the temple. arati was offered to them by a "qualified" brahmana and he threw the flower he had offered at them instead of placing them properly. one of them hit radharani in the face. i nearly attacked him right then and there. if that sort of impersonalism toward the deity is qualification simply because he knows all the correct steps in a puja, well forget it! qualification means nothing!! if the prema bhakti is not there in the relationship and it is a show, then those people should not get near a deity!
if you establish a relationship with these orphaned deities, do not give them up for anything! krsna will manifest himself to you when HE wants to and he will leave when he wants to. prema bhakti will keep him. you can always tell if deities are pleased or not by srimati radha's expression. she will let you know if your worship is up to her standards or not.
i hope this helps some. i also hope these deities end up in the right environment! please let us know!