We do not - your support (whether physically at the wedding or words of support) is what matters the most! We also realize Seattle is very far from everyone and we want this to be as least stressful as possible for everyone.
There are many options across Seattle and the Eastside. Generally if you want to do more of the city/touristy stuff, downtown Seattle hotels will be most accessible. Most hotels downtown will make you pay for parking and there is more traffic, but you can walk or scooter to many things depending on hotel. If you're into outdoors or leisure (less traffic, quiet, parks, lakeside beaches), the Eastside will be a better option (particularly Kirkland or Woodinville; Bellevue is still a pretty big city).
It does rain quite a bit, but Summer is actually really dry here - late June will be closer to the dry weather. Wedding ceremony will be uncovered, so we do recommend bringing a jacket or umbrella just in case things get wild. Would also recommend a jacket in case it's a chillier day. The reception will have both indoor and outdoor spaces for eating and hanging out.
We would recommend getting a rental car or carpooling. The metro unfortunately does not cover too many areas and isn't well connected between Eastside and Seattle. There will be valet for anyone planning to drive to the wedding. Uber/Lyft is also widely available.