you can refer to the UG page 18 for instruction. http://www.tp-link.com/res/down/doc/TL-SG105E_V2_UG.pdf

It is recommended to use dynamic LAG, which is called LACP, you can refer to the FAQ below for help: http://www.tp-link.com/en/faq-991.html

For your case, I think the 802.1q is more suitable for you and here is a FAQ that might suit for your case.

I am not very sure about what you said, but I know the R470T+ supports telnet access but it has little command we can use. Maybe you can refer to the UG for help.

I have the same problem recently!!! But my NO-IP account is OK. Did your problem happen recently? I heard this is because the latest update of the DynDNS, did you try to contact the DynDNS supporter?