For the seals I have one of theses which works OK
https://www.ebay.co.uk/itm/152712043967
Cannot help with the water pump as I have never done one
With the SA I can only suggest daily dosing with penetrating oil for about a week then heat (blowlamp on the eyes of the SA) then a length of 10mm studding a stout washer that matches the SA spindle diameter (20mm) and a socket that fits over the OD of the spindle on the other side and try to draw it out. If you are hitting it with a hammer the drift has to be soft (aluminium, copper or brass) as hitting the SA spindle can bell the end and then you are in deep doo doo.
If it was me I would insert the studding wind it up to about 100nm and heat it with the pressure still on and failing any movement use the drift - good luck