What to do first,endorsement or visa screen?

You can do both at the same time if money isn't an issue but if you need to prioritize then applying for visa screen would be best in my honest opinion.

You can start the petitioning process already w/ your Oregon license even though your employer might be in another State. Remember that it only needs proof of passing either NCLEX or CGFNS exam (if applicable). Plus we have been hearing that the Visa Screen certificate will be a requirement to start the petitioning process very soon, if it's not already. USCIS has already attempted last year to make it a mandatory requirement to just file the I-140 (in addition to the proof of passing NCLEX or CGFNS exam) but as always some lawyers or law groups/firms complained about it because it was in the middle of the fiscal year and tantamount to changing the rules during the middle of the game and therefore USCIS reversed it w/in a week that it was imposed.

Start of the next fiscal year would be this Oct. and since all the EB categories are either currently retrogressed or unavailable, this would be the best time to implement it again if it's not being implemented already.

I agree with that as well.

Your welcome. Glad to have helped.