pa-advice lang po...

i have a boyfriend po, meron syang 2 anak sa unang babae but they were never been married. he just gives support to the 2 children. now po, we already have a child narin, and are planning to get married very soon.
1. he would like to get the full custody dun sa first child nya sa unang babae because wla namang work ang babae at the same time puro hingi nalang kasi ng pera most of the time. what would be the legal process na mapagdadaanan just in case?i know po na di kasi pwedeng basta nyang kunin kasi sa mother talaga custody pagka ganun. btw, the child is already 7 years old.
2. if ever na gusto ko pong ituring na anak yung 1st child sa 1st girl at kukunin na namin sya para kasma na namin sya sa bahay,for adoption na po ba yun? papano din po kaya process nun?
3. nagaalala ang partner ko, if ever daw na iksal kami baka hndi na daw maconsider as beneficiary yung 2 anak nya sa unang girl.. dahil baka yung anak lang namin ang maging legal beneficiary. pls advise...
4. "if and only if" lang po, may mangyaring masama sa partner ko (cross fingers), at hndi pa kami nakakasal, may habol po ba ako sa knya or wla?pls advise...


thank you in advance.. GBU