Any of the major barrel makers should be able to help you - Lija, McMillan, etc..
Yes.
$300-$450. This rifle was made either by Heym or by FN. If a true Mauser action it will be made in Belgium by FN. Otherwise it will be a Mauser 3000 made by Heym.
.270 has been around since 1925. You will have to contact FN to check on the sn.
100-1000 or more depending on specifics
Fabrique Nationale or FN is the maker.
hard to say for sure, but you should try Numrich Gun Parts Corporation. This was a FN Belgian Mauser action, with Sako trigger, so depending on what parts you need, either FN or Sako will also have parts interchangeability. FN is still around in business.
It is an FN made Mauser 98 action worth $300-$400
No
DO NOT ATTEMPT TO FIRE UNITL EXAMINED BY A COMPETENT GUNSMITH!!!!!!!!!!!!!!!! Danger, Danger, Danger
The serial number should be on the front barrel band, in some cases it is on the barrel.
Impossible to answer without more information. Generally, Western Field rifles were made by Mossberg and Marlin, but some were made by FN and were Mauser actions.
100-1000 depending on specifics