Zav/zavva/nidda give off tumah in many ways. מגע- contact. משא- someone carries them even w/out touching. מדרס- any designated time for siting/lying becomes an ab HaTumah when they sit/lie on it. Covered stone- when sitting on stone, they give tumah to things beneath the stone. היסט- If the zav carries an item without contact.

How many of those tumos does an idol have? It certainly gives tumah with מגע- contact. Acc to rabba, it also certainly gives tumah to someone carrying it, but acc to r elazar, only r akiva has that stringency. Acc to rabba, r akiva holds it gives tumah of covered stone and of היסט. (Acc to r elazar no one holds an idol has these tumos) An example of an idol giving היסט would be if an idol is one side of the scale and it weighs down the scale, supporting some food on the other side.

Non Jewish men and women are rabbincally all treated like zav and zavva in order to discourage connection. This is a fill fledged tumah jsut like zav and Zava

If an idol is in pieces, the gemara in unsure if it’s still tamei. The gemara has two versions of the safek: either in a case where only a professional can repair the idol or when anyone could .

Since an idol is compared to a dead body, we derive that only an idol bigger than an olive gives off tumah. However, a tiny idol is certainly forbidden in benefit.

A boat does not accept tumah. Our tanna drives this form the pasuk comparing the boat to the sea- jsut as the sea isn’t susceptible to tumah, a boat is also not. Acc to this, it wouldn’t matter if it’s a big or small boat or what material it’s made from.

Chananya has another source for a boat not accepting tumah. The Torah writes wood accepts tumah next to sack: just as Sack has a receptacle and can be moved empty of full, so too wood kli only accepts tumah with קיבול that can be moved even full. A big wood boat can’t be moved full and is therefore Tahor. An earthenware boat or a small wood boat would be tamei though.