Trouble with internet (WiFi and cellular) and loud speaker.

Hello there!

My best friend gave me her cellphone to get it fixed. She asked first (a year ago) in a store and they told her that her cellphone was dead due to the logic board was damaged. It didn't give me that impression, so I offered myself to have a look at it. iTunes recognized the cellphone, so the logic board was working (that was my thought).

Then I replaced the screen and it worked, but the iPhone got stucked in the apple logo, and iTunes asked me to update/restore. I tried to do so (both options) but an error showed up (error 200x); I replaced the charging port (the whole flex) and it didn't work, we were stuck on the same error 200x. I went back to its old charging port.

Next I did was replace the battery, and finally it worked!! the phone was up and running no problems (by the time, I had not checked up that everything was working ok).

Next problem: the battery would not charge past 25%. It drained to 1%, the cellphone shutted down, and there we were again: stuck at apple logo (what a pain) when I tried to charge it.

I connected the battery to my battery tester, charged it a little bit. While that was happening, I replace once again the charging port to the new one. Connected the battery back in the iPhone. Everything working (that was what I thought, once again I was so wrong).

Vibrator working ok, same with front/rear camera, earpiece speaker, touch screen, home button. The cellphone got nice signal, I could make calls, a couple of messages came thru (I put my SIM card to test it). BUT, 3 things are not working after my infinite tries: WiFi, cellular internet and loud speaker.

The cellphone recognizes the cellular internet band (E, 3G, no trouble), also recognizes WiFi networks and connects to them, no problem. But it will not surf through the internet, Youtube: error while connecting; Safari: connection can not be made; iCloud is asking me to accept new terms, when I type the password of the iCloud account and press go: connection with the server failed.

That is not all, the loud speaker is not working either, music will not be played out loud; and pressing on speaker during a call does not make any sounds. Typing does not make sounds, when getting calls the cellphone do not play the 'ring tone melody'.

Now I am stucked here, I do not know what to think. I mean, how come the cellphone recognizes WiFi networks, connects to them; recognizes its own internet band, but does not work? What do I do with the loud speaker?

I really hope you can help me.

Thanks.

-C

EDIT1: Airdrop works (I transfered some pics to my mac). When I connect the airphones, I can not hear any sound.

EDIT2: Now the cellphone will not charge, 30 mins ago I connected the cable to charge it (it was 63%), and the battery % has not even gone up in 1%. I am able to see a lightning bolt beside the battery icon in the status bar, which means it is actually 'charging'. What can be happening? The battery? The charging port? Motherboard?

EDIT3: Photos attached.